


Sleep Paralysis

by hetzi_clutch



Series: Sleep Paralysis [1]
Category: Doctor Who & Related Fandoms, Doctor Who (2005)
Genre: Angst, Canon-adjacent, F/F, Gen, Horror, Lots of it, Multiple Universes, Mystery, Other, Romance, The Time War, Timey-Wimey, and other tasty bits from the doctor's past, basically i took timey-wimey relationships and ran with it, different timelines, i guess?, i wasnt sure if its that scary but my betas said there's 'proper spook', nontraditional love story, scary stuff, so im gonna go with that, srsly whatever story you're expecting this is not it, thasmin, this is NOT a fucked up relationship btw, this is about facing your past mistakes and DEALING with them, we dont do that in this house
Language: English
Status: Completed
Published: 2019-05-03
Updated: 2019-05-25
Packaged: 2020-02-16 10:38:14
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 11
Words: 36,398
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18689809
Author URL: https://archiveofourown.org/users/hetzi_clutch/pseuds/hetzi_clutch
Summary: There's something wrong with Yasmin Khan.





	1. Chapter 1

**Author's Note:**

  * For [wreckageofstars](https://archiveofourown.org/users/wreckageofstars/gifts), [hellynz](https://archiveofourown.org/users/hellynz/gifts), [Ohcaptainswanmycaptainswan](https://archiveofourown.org/users/Ohcaptainswanmycaptainswan/gifts).



> You guys, what's up? I'm back at it with what was supposed to be a oneshot that spiraled out of control and is now many chapter, lol. Anyway, I really, honestly, don't know what this is, but I hope you all enjoy it. Also if by the end of it you're like 'wtf', that's fair too.
> 
> A few notes:  
> -The inspiration for this story, and the 'fanon', I guess you could say, from which this story is heavily based upon is from a story called Time v3.0, by Teyke, which you can find at https://archiveofourown.org/works/471497/chapters/815855. I highly recommend checking this story out, it's literally one of my all time favorites. Seriously, it's a masterpiece. And I can thank that story for this one.  
> -This story is finished, and if it weren't for the fanzine chat, that would have never happened. Seriously, I came really close to abandoning it three times, and the only reason I didn't was because of them. So I gotta give a big shoutout to the whole fanzine chat, for all the support and motivation (and death threats).  
> -This story is the first time I used betas, and I'm lucky enough to have three (IKR, trust me, I need three) amazing betas, who have worked with me on this story. So a huge shoutout to ohcaptainswanmycaptainswan, hellynz, and wreckageofstars, for the enormous amount of help they've given me :)) Yet three more reasons this story isn't gathering dust in a file.  
> Okay, I'll stop boring you guys, and let you all get on to the story. And I promise, the next note won't be this long.

_“I have love in me the likes of which you can scarcely imagine and rage the likes of which you would not believe. If I cannot satisfy the one, I will indulge the other.”  
-Mary Shelley, Frankenstein_

The Doctor tries, when at all possible, to see time in a linear fashion.

But crashing through the roof of a train, she figures, is enough to bang anybody’s head around. 

She wakes up and tries to focus on what’s happening in the moment, but it’s _hard_ when there are so many futures swimming around in her head. There’s an alien right in front of her, but she’s already seeing what it might and might not do, and can’t figure out which one will actually happen, until it zaps them all in the neck and neatly deposits six DNA bombs into their nervous systems.

And she sees that she’ll get them out—which of course she will, she always does with these things—but she can’t see the present linking to that future, has to feel her way around it blindly, searching for the right sequence of events to match up with that positive outcome.

And then it only gets harder when she turns around, and runs smack dab into _her._

The—bloody hell, she can’t remember her own name—stops and stares. There’s a boy, or maybe not a boy, a man, standing in the aisle, next to a police officer, and that police officer happens to be _her._

She takes one look, and nearly keels over from the pure illogicity of it. Dimly she registers a yellow safety vest, pretty features and a confused look, but mostly she’s trying to stop her head from spinning right out of control, because the girl—she is a girl, isn’t she?—doesn’t make sense, _at all._ She’s there and she’s not, all at the same time, and she doesn’t exist, has never existed, but she’s got a million timelines swimming off of her— 

“Uh, excuse me, madam—” the girl tries, and she has to raise her hands to her ears in a desperate attempt to block it out because _wait,_ this isn’t supposed to happen, she’s supposed to brush past them with an indignant ‘fat lot of good you two were!’, and the girl calls out ‘hey!’ but instead somehow this present is occurring, and—

“Hang on, why’re you calling me madam?” Distantly she realizes that in a different timeline she would have uttered those words three cars farther down, but in _this_ present she’s still staring, actually squinting now, trying to figure out why this girl is standing in front of her, when by all logic, she shouldn’t be.

“Um…you’re a woman?” the girl wrinkles her nose in confusion, then takes a step back, because now she’s stepping up closer, right into the girl’s personal space to get a good look.

“Excuse me, what are you doing?” the girl asks, and possibly by accident shines her flashlight directly into her face.

“Yasmin Khan.” She plucks the words from one of those timelines swirling around her muddled brain, and relishes the way the name sounds on her tongue. “Yaz to your friends.”

“How did you—” Yaz stares open-mouthed, and that’s precisely when warning bells go off in her head, because she's veering down a timeline that doesn't _fit;_ None of this should be happening, she realizes, or at least in this order, and she may be out of practice but she's still a Time Lord, so with an enormous shove she pushes this one to the side, stuffs that timeline away, and drags in the one that _should_ be happening—

“Fat lot of good you two were!” she says, and pushes past them to make her way down the train. Distantly, she notes Yaz’s indignant ‘hey!’ and feels a sharp stab of relief. She's fixed it, sort of.

And, as it always with the lesser species, they don't even notice a thing has changed. To them, she has never stopped and stared, never flickered briefly down the wrong path. It's all as it should be.

But Yasmin Khan notices. Of course she notices.

————

By the time the night is over, Grace is dead, Tim Shaw is gone, and the Doctor is back to viewing time in a linear fashion. Mostly. 

She stays for the funeral, even though the headache that is Yasmin Khan stays too, because she feels she owes it to Graham and Ryan. And it's a bit easier, now that she’s more or less back in order, to sit comfortably in one linear timeline rather than spreading herself between all the ones that might. She prefers, whenever possible, to let time run its own course. 

Messing about, even for someone like her, is always a dangerous proposition. 

But Yaz catches her after the funeral, just as she’s about to slink off, and immediately dips them both into the kind of murky conversation she hates. It had been supposed to be all three of them there, and Yaz, perfectly innocent, would ask about her family, and the Doctor would say something vague and meaningless (it’s impossible to sum them up in simple words, anyway), but instead she ends up alone with Yasmin Khan, whose very presence makes the Doctor’s brain hurt, watching as her lips form a question she very much does not want to answer.

“Back on the train,” Yaz says, feeling out the words carefully, “You did something, didn’t you?”

“You’ll have to be more specific,” the Doctor replies, though she already knows that such a response won’t help much. “I did a lot of things on the train. One of them being falling through the roof, which, by the way, I do not recommend.”

“Oh, uh—” Yaz blinks, taken aback by her flippant answer, but drives down her path all the same. “Yeah, that must have really hurt. But I mean after that. You—you—”

She’s struggling now, and the Doctor watches her, torn, because she should have yanked them back on the right path ages ago, the nice one with the others included, but at the same time it’s fascinating to see a human try to sum up what Time Lords can barely describe.

“You—you _did something,”_ she delivers at last through gritted teeth. Her eyes narrow in frustration. “I don’t know what it was, I don’t know even how to describe it, but you looked at me, and you told me my name, and then a second later—or, not a second later, it was at the same time—you said something different, and it all happened differently, but I don’t know _how.”_

She takes in a deep breath on the last word and lets it out in a huff, and the Doctor only too late realizes she’s standing there with her mouth hanging open in awe, because, once again, Yasmin Khan is not making sense. Or rather, she’s putting words to concepts she shouldn’t be able to see, let alone describe, and the longer the Doctor stares, trying to make sense of things, the farther she seems to spin away from it.

“You shouldn’t have seen that,” she says honestly, and steps forward, moving in a tad too close. “You shouldn’t be able to _describe_ what you just described, let alone realize that something happened. How did you do that? How did you know?”

“I—” Yaz is leaning back, drawing uncomfortably away from the Doctor’s scrutinizing gaze and too-close proximity. “I-I don’t know. Why can’t I be allowed to see it? What did you _do?”_

The Doctor studies her, and doesn’t answer. She’s not sure this is a conversation she wants to have, partly because it’s swimming towards a shrouded future, and she’s never liked shrouded futures, and partially because staring at Yasmin Khan is giving her a splitting headache. She can’t decide if she’s talking to a person, or a shadow.

“Yasmin Khan,” the Doctor murmurs. “What _are_ you?”

Yaz opens her mouth, maybe to answer, maybe to return the question, but the words never make it out, because before she can the Doctor steps back, and starts to close off the timeline. 

It’s too risky, she decides. Something about Yasmin Khan jars violently with the whole time-space continuum, and while normally the Doctor loves a mystery, she currently has a missing ship and an urgent need for a change of clothes. Higher priorities.

She wouldn’t usually pull such a massive shift so soon after the one on the train, but she’s sort of desperate to escape this conversation, so she reaches out and starts groping through realms of possibilities. She finds the one they should have been heading down, had the Doctor not let herself get sidetracked, and this time, she doesn’t shove it in. Instead she folds it carefully to the moment, letting it flow around them like water over rocks, sweeping away the debris of a conversation that never happened.

“What did you mean in your speech, you thought you’d run out of time?” she asks Graham, keeping an eye out for Yaz, who’s glancing around at the others as if she’s only just noticed their presence. She can tell by her expression that she’s spun it much smoother this time; she blinks, once, then settles in listening, just as she had been the entire conversation.

————

She tries to get her TARDIS back, and ends up yanking them all into empty space. Two spaceships which never should have been there scoop them up, and by the time Yaz wakes and stumbles to the front of the craft, the Doctor has seen enough to know they’re crashing. 

She’s not entirely sure she can pull them out of this one, either. The pilot finally agrees to jettison the back end, but by then they’re careening uncontrollably, the Doctor is trying to steer and take care of Yaz at the same time—it’s her first time out in space and they’re crashing, _bless_ —and as soon as she sees the descent pattern, she can tell they’re not going to make it.

She lies to the pilot and straps herself in, even though she knows it’s pointless, and rifles through possibilities. There are plenty, but nearly all of them involve a fiery death, and the ones that don’t whip by too fast for her to catch. 

That’s the problem with _crashing,_ she thinks through gritted teeth, as she jerks back the controls. It all takes seconds, and sometimes, even with all of time at her fingertips, seconds just aren’t enough.

She slides them into an optimistic timeline that gets them through the atmosphere, but as they hurtle to the planet, the surface looming large before them, she can’t find another one that works. They all end in death, every one, and the ones that don’t are too far away to grab without upsetting the temporal present. She switches controls, and flicks a switch that doesn’t matter, and tries to look like she’s doing something because it’s too late to even tell the others that it’s too late. The beige of the planet fills their viewpane, she pulls back on the controls, hears the others screaming, and wishes she hadn’t told Yaz she would save them.

Then, just as they’re about to smash into the planet, she feels something wrench in the space-time continuum. The entire present shifts sideways, screeching like rusty hinges into a possibility that is _too damn far,_ and then jolts roughly into place. The brakes respond suddenly, and she yanks them into position, the entire ship heaving backwards with it. Sand blows over the viewpane, blinding them, but she doesn’t care because a moment later the ship tips forward and settles, right into an impossible present.

They’re alive. They shouldn’t be.

And the Doctor hadn’t changed a thing.

She glances behind her, sees a hand gripping the edge of her seat, and follows it up to Yaz’s face, pale and wild-eyed with fear, her breath coming in short, quivering gasps. She clearly thought they were about to die. The Doctor’s reassurance hadn’t done a thing.

But apparently Yaz had.

The Doctor stares at her, and despite the pleasant, buzzing relief of survival humming through her veins, she can’t help but feel a surge of fear.


	2. Chapter 2

**Notes for the Chapter:**

> it's funny (and fitting) that, whereas I usually write fics in order, from start to finish, a good part of this fic was written out of order. timey wimey, right?

The Doctor stays away from any overt temporal shifts after the crashing ship, mainly because she shouldn’t be mucking about with time in the first place. It’s a Time Lord’s second nature to shuffle through possibilities like a deck of cards, but that doesn’t mean she can always force the right hand. Even in the days before the Time War, when there were entire societies of temporal powers at her back, it was a tricky proposition.

There were reasons only a few made it through the Academy.

But she can’t stop from side-eying Yaz, even when she side-eyes her back, because she can’t stop remembering that shift on the crashing ship. Clumsy and reckless, like a child shoving sticky putty into a disc receiver; it shouldn’t fit. And yet it did. She’s not sure what to make of that.

She’s not sure what to make of _Yaz_ , either, and not only because she gives the Doctor a headache. She seems, in all aspects, to be a regular human girl; kind and brave and a little reckless, intent on doing the right thing. Normal, if she looks at her the way humans do, seeing only through space, and not time. 

But the TARDIS doesn’t like her. She keeps trying to shake them off, throwing them in all sorts of directions even though the Doctor _tells_ her she’s taking them home. And when they get there, the Doctor is quick to shoo them off, successfully avoiding a timeline where Yaz asks them all round for tea, and is about to hop into the TARDIS and take off, leaving the whole temporal mess behind, when she spots a pile of unlikely-placed rubbish just off to the side.

“What’s that?” she asks, and then nearly groans as she feels the possibility she’s walked _right into_ solidify. She can’t tell what it is, yet, but she can make out enough to know she isn’t leaving any time soon.

“Oh, hey, that’s the rubbish my dad keeps in the house.” Yaz sidles up beside her and points, amusement twitching at her lips. “I recognize those exact cartons. Reckon me mum tossed it all out here on the way to work. She’s ‘bout ready to kill him about it.”

“Rubbish?” the Doctor frowns, and steps forward to examine it, just as Yaz’s phone goes off. She hears her answer, then a quick gasp. 

“I—I have to go,” Yaz says behind her, and she turns to catch sight of her stricken face. “My mum—she’s just been fired.”

“Oh, Yaz—I’m sorry to hear that,” the Doctor says, and she is, only there’s a small pit of relief in her stomach. Separated at last. Graham and Ryan have already gone home, and now Yaz is off to her mum, and soon the Doctor will be gone too. Nothing to worry about.

The timeline she’s locked into tugs at her, but she pushes it away petulantly. Probably. She’ll probably be gone soon.

Yaz leaves, and the Doctor stays a little longer than she should have scanning the rubbish. She doesn’t realize her mistake until a woman runs screaming out of the estate, babbling something about giant spiders. The Doctor goes with her to investigate, albeit reluctantly, and they track the problem down to an enormous, not-yet-opened hotel. Mid-way, Graham and Ryan call her up, asking about cobwebs, and she decides to drag them along just to make sure they’re safe. Half an hour later, they all end up together in a spun-web haunted house of a lobby. 

And of course, Yaz is there.

They figure out the problem and escape the hotel without a single bit of temporal messing about, and the Doctor is just a tad pleased with herself on that one. She doesn’t like doing it around Yaz, not when she gets the unsettling sense that she _notices. ___

__The timeline they’re in segues nicely into another where Graham and Ryan ask to keep traveling with her, but Yaz is absent, and the Doctor isn’t entirely displeased. She’s not in the mood for a mystery, and Yaz might as well have a big M taped to her forehead—when she’s even there, temporally speaking. Because there are times when she catches Yaz out of the corner of her eye, though she’s standing directly across the room, and there are times that she looks right at her and can’t see a damn thing. It’s like looking at a solid ghost. It irritates her._ _

__She’s all ready to greet her new friends-turned-traveling companions, and is standing excitedly by the console, balancing on the balls of her feet, when the doors open. Three, rather than two, walk in._ _

__The Doctor rocks back on her heels, and catches her frown just in time. Graham and Ryan and Yaz stand before her, fear and hope and excitement all mixed up in their faces. She glances to Yaz, and she’s flickering in and out of existence. Again._ _

__“So you want to come with me, then?” she prays her voice doesn’t sound too flat, which isn’t fair, because only a moment ago she’d been excited. She hadn’t expected this, for Rassilon’s sake, and it doesn’t make sense, because she’s a Time Lord; there isn’t much she can’t expect._ _

__“If you’ll have us,” Graham says, and Ryan shrugs, gives her a half-smile._ _

__“Beats studying for my NVQ.”_ _

__Yaz smiles, tinged with uncertainty. “I want to see more. More of the universe.”_ _

__The Doctor stares at her, and the ghost of a sentence never about to be said hangs in the air._ _

__“I can’t promise you all it’ll be safe,” she says, and hopes it’ll dissuade them. Well, one of them. “I can’t promise you’ll come back the same people as you were before you left.”_ _

__“I think that’s good,” Graham says, and Ryan nods. Yaz just looks at her, and bites her lip. She doesn’t say anything._ _

__The Doctor swallows, then looks between them. And nods._ _

__“Right!” she says, false cheer straining to turn real. “Where to, fam?”_ _

__————_ _

__At first, it’s just a pain in the neck. She’s got two new friends, and a tag-a-long she can’t even look at without getting a headache, thanks to the mess of incomprehensible timelines swirling around her. The Doctor’s never been one for painkillers of any kind, but after a couple weeks of pounding headaches, she gives in and stops off at a moon which sells Time Lord-safe headache pills._ _

__It helps, to the extent that it keeps her head from bursting whenever she so much as looks in Yaz’s direction._ _

__The TARDIS doesn’t take any more to Yaz this time around than she did before, and runs the Doctor ragged just trying to steer. She doesn’t seem to know any more on the subject than the Doctor does either, or if she does she’s staying irritatingly silent, which leaves the Doctor with nothing to do but sit back and sulk over the fact that she’s stuck gallivanting across the universe with some kind of paradox._ _

__She should have just said _no.__ _

__Then again, that’s not entirely fair, and she knows that, deep down. Yaz might be painful to look at, and slightly scary to consider, especially since she doesn’t seem to align _at all_ with the rest of time and space, but she’s not _bad._ In fact, the Doctor has a sneaking suspicion that she’s actually quite good, and a whole host of other things. Kind, and stubborn, and a little reckless, with a view of morality that’s endearingly naive. She just wants to do _good,_ it seems, and see the universe, which only makes the Doctor feel more guilty about the fact that she doesn’t want her along._ _

__She does try, if only to ward off suspicion, because she notices Yaz watching her, sometimes, a quiet, inquisitive look on her face, and isn’t sure what it means. Like she’s trying to figure the Doctor out. Which is funny, because for the first time in her incredibly long life, the Doctor thinks she might be the simpler side of the equation._ _

__Because whatever Yaz has sussed out about her, it’s definitely more than what she’s sussed out about Yaz._ _

__She’s not sure it works, but she turns on the charm and makes jokes and jumps around and does have a lot of fun, even if it’s a little forced. And she tries, tentatively, to like Yaz, even if she isn’t sure she understands why Yaz decided to come on their little adventures in the first place. By all rights, she shouldn’t have. There’s an impossibility about it, a missing piece of the equation that the Doctor can’t quite grasp, no matter how hard she tries._ _

__(Though, to be fair, it’s a little hard to get a read on Yaz when the Doctor can barely look at her.)_ _

__And then, she finds the missing variable in what might be the most embarrassing of ways._ _

__She gets tied to a log and thrown into a lake._ _

__In retrospect, the Doctor figures she should have seen the witch thing coming. Probably would have, if she weren’t still getting used to the whole ‘new gender’ thing. It’s easy to forget, once she gets the little things figured out, the undergarments and new hairbrush and the special shampoo Yaz insisted she buy. So it’s a bit of a shock when she goes snooping around the forest for a bit of mud tendrils, and ends up getting accused of being a witch._ _

__She’s not too worried about getting out of this one, thanks to that weekend with Houdini, and she actually feels fairly confident about the whole thing, right up until Becca dunks her in the lake and she realizes the chains are tighter than she expected._ _

__She doesn’t even have time to hold her breath, before they plunge her underwater. Talk about unfair._ _

__She employs all the tricks Houdini taught her, and then a few of her own, because it’s not as if she doesn’t have experience, but none of them work. After a few minutes she starts to worry, then panic, and then her respiratory bypass system starts to give out on her, and the Doctor realizes that she’s actually going to die._ _

__And all she can think is, _what a way to go.__ _

__Her vision starts turning black, even as she’s still struggling, and she forgets to hold her breath, lets her mouth flop open as her head falls forward, and the water rushes into her mouth. She chokes immediately, because of course her first instinct upon opening her mouth is to _breathe,_ and then she really starts to panic. Pure instinct takes over, and she thrashes, trying to escape, but it’s no use. The Doctor looks up to the watery light above, and wonders if she’ll have time to regenerate. She doesn’t think so._ _

__The timeline groans and shifts, pulling like a stuck handle, which is not good because the Doctor knows it’s not the kind of stuck handle that should be jimmied, otherwise _she would have done it herself, damn it._ But it moves anyway, with great reluctance, and she can almost feel the universe tearing apart, but in that moment she can’t bring herself to care, because then the log heaves to the surface, carrying her with it. Too early. _ _

__She chokes and coughs up water, as the crowds look on in awe and horror. Horror, and three relieved faces, two looking worried and one looking absolutely devastated, her hands clamped over her mouth, and even as the Doctor vomits up what feels like gallons of icky lake water, she can’t help but stare in utter astonishment. Not because of the timeline, worrying as that is, since she’s long since suspected Yaz was capable of doing that._ _

__But because in all those months trying to warm to Yasmin Khan, the Doctor had not once suspected that Yasmin Khan might have warmed to her._ _

__————_ _

__Once the missing puzzle piece falls into place, the Doctor starts seeing it everywhere. She’s not sure how she missed it, though she suspects those nagging migraines had something to do with it._ _

__It's a little confusing, if she's being honest, because she's not sure how she won her over. She hasn't even been trying, not in the way she usually does, has in fact been half-hoping that Yaz will eventually pack it up and go back to that policing job she's so proud of._ _

__And once the realization sinks in, she can't help but feel a hot prickle of shame. Yaz has gone and saved her life, nearly ripped apart a timeline to do it, and here is the Doctor, sitting around dithering over whether she even _likes_ the girl. Sure, she'd let her on the TARDIS—despite the TARDIS’s best efforts—and sure, she'd been, well, _nice._ _ _

__But she hasn't been a friend, not really._ _

__And it's about time she should start acting like one._ _

__She's not sure it's the right reasons to dig into a friendship, but she's picked up less for worse. Anyway, she's long over being stand-offish; had enough of it in the last regeneration. She's still surprised she managed to amass friends, back then._ _

__(A name comes to her lips at the memory, a name and a death that never should have happened, but she tucks it away with a promise. She’ll do better, this time around. She _will_.)_ _

__She starts by inviting herself over for tea, next time they stop off in Sheffield. She's half-hoping Ryan and Graham will come along, but it turns out they have things to do, so it's only she who goes knocking on Yaz’s door mid afternoon, an uncertain smile on her face._ _

__Yaz opens the door, and to the Doctor’s slight chagrin looks just as out of place standing in her own apartment as she does standing in an (admittedly grumpy) TARDIS. She's still sort of there and sort of not, and it's a bit hard on the eyes, but she's wearing a smile, so the Doctor brightens up her own and steps inside._ _

__“Hiya, Yaz!” She feels like she's trying too hard, but it's difficult to gauge. Yaz seems to buy it. “Nice place you got here. Ooh, do I get to see the fam?”_ _

__Yaz wrinkles her nose. “Just my sister, sorry. Tried to kick her out but she won't leave.”_ _

__“I heard that!” comes a muffled shout from down the hall. The Doctor peers around the corner and spots a pretty girl a few years younger than Yaz, one foot in the entrance to a bedroom. She catches the Doctor’s eye, and gives her a look that's highly suggestive, for reasons the Doctor doesn't know._ _

__“Nice to meet the girl she keeps talking about,” she says, and waggles her eyebrows. The Doctor stares, nonplussed, as Yaz leans around the corner and glares._ _

___“Room,_ Sonya,” she hisses, and Sonya throws her one last confusing grin before she slips through the door, letting it bang shut behind her._ _

__“Sorry.” Yaz turns to the Doctor, grimacing. “She's a pain in the arse, but she'll stay out of our way, I promise.”_ _

__“Oh, it's no problem,” the Doctor says, and follows her into the kitchen. “I know sisters. Used to be a sister, actually.”_ _

__The words sound funny, familiar to her ears, but she shakes it off and focuses on Yaz, who is busy reaching up on her tiptoes to nab a jar of tea bags from a shelf._ _

__“Careful there,” the Doctor calls, because it's just a tad too high. “Not that kind of doctor. Least, haven't updated my degree.”_ _

__“It's fine,” Yaz says through gritted teeth. Her fingers barely brush the bottom of the jar. “Sonya puts it up here to torment me. She thinks it's funny she's taller.”_ _

__“Are you the older one?”_ _

___“Yes,”_ Yaz growls, though the Doctor gets the sense her ire is directed at her sister, rather than herself. Yaz’s fingers scrape uselessly at the bottom of the jar once more, and the Doctor can't help herself; she stifles a giggle._ _

__It's sort of funny. The entirety of time and space fractures around her, and Yaz is confounded by her younger sister._ _

__Unfortunately, Yaz catches the sound, and turns, her glare zeroing in on the Doctor._ _

__“Oi,” she scowls, only now she's reaching for the jar without looking, and it doesn't take a Time Lord to see what's about to happen. The Doctor lunges forward just as the jar tips, and thanks to her extra inch of reach manages to intercept it before it cracks right into Yaz’s skull._ _

__Yaz staggers backwards, partly out of surprise and partly because the Doctor’s over-exuberant lunge leaves her with no other place to go. The Doctor cradles the jar in her hands and turns to Yaz, a cheeky comment about height ready on her lips._ _

__And freezes._ _

__Yaz isn't looking at her. She's staring dazedly at the broken glass and tea bags littering the kitchen floor. Blood cascades over her eye, drips onto the linoleum. There's a shard of glass caught just under her hairline. As the Doctor watches, she touches a shaky finger to her forehead, and brings it away tipped with blood._ _

__The Doctor simply gapes. Her eyes fall to the jar in her hands, clean, unbroken, and then to Yaz again._ _

__“Yaz—?”_ _

__Yaz looks up, and for the scarcest second there’s something— _different_ in her eyes. A blink, and then she smiles, abashed._ _

__“Okay, so maybe I wasn’t tall enough.” Her smile drops into a frown, a crease appearing between her brow. “I could kill Sonya for that. She could have broken my head in!”_ _

__“I—” the Doctor is still staring, open-mouthed. Yaz appears completely whole, no sign of blood nor broken glass. The tea bags are safely contained within the jar._ _

__Nothing happened._ _

__“Sonya!” Yaz turns and stomps off to the hallway, leaving the Doctor standing gobsmacked in the kitchen. The jar still dangles from her hands, and she sets it shakily on the counter._ _

__An exasperated answer, from down the hall. _“What?”__ _

__“I’ve had enough of you and your bloody tricks, that’s what! I’m phoning mum—”_ _

__The Doctor stands there, and resists the urge to run._ _

__She nearly does, then and there. It would be easy. She's run before, from things like Yaz. She's been doing it her whole life, anyway. She ran from Gallifrey when she was but a young old man, and she ran when the Time War started and she couldn’t bear to take part in it, and then when she finally gave in and fought, she really spent most of that time running too. Ran from battles and horrors she'd helped create, the Nightmare Child and the Paradox Locks and Davros’s ship, when she could have saved him. Ran from her choice, at the end of the war, when there’d nearly been no-one left to make it. And then, when the war had ended and she landed on earth with both feet, or sort of, she’d started running right then and hadn’t stopped, not once._ _

__The Doctor stands there and thinks of about a thousand excuses she could make, thinks of how easy it would be to dash off to hide safely in the TARDIS. But then she thinks of a promise, and a resolve to do better, and instead grits her teeth and puts the kettle on, as she listens to Yaz rip into her baby sister down the hallway._ _

__Yaz appears just as the kettle starts to sing, pink-faced. “Sorry about that,” she mutters, and balls her hands up, stuffing them into her pockets. “She’s an absolute brat, and she’s only two years younger than me, I’ve no idea—”_ _

__“It’s alright,” the Doctor says automatically, and removes the kettle from the stove. It’s a relief not to look at her, but instead to focus on the comforting act of pouring tea, a thousand times worn-in. She’s scared if she looks up, she’ll see that same flicker of _something_ in her eyes. Something off, something wrong. She can’t even name it._ _

__“Like I said, I know sisters. Had a few myself. They can be a right pain, but they’re worth it in the end.”_ _

__She glances up on the last bit, and with some relief notes that Yaz isn’t look directly at her, but has her gaze on the kettle. She shrugs, clearly unconvinced._ _

__“Yeah, I suppose. It’s just annoying, though. I mean, I’m supposed to be the one giving her a hard time. But she’s always giving me crap about my job, and how I don’t have any friends—”_ _

__“What do you mean you don’t have any friends?” the Doctor’s head jolts up, and she nearly spills the tea she’s pouring. A few drops splatter onto the counter, and she wipes them off with her sleeve._ _

__Yaz stares at her, puzzled. As if it’s obvious. “Well, I weren’t exactly the popular kid in school, and like I said I got picked on a lot, so…”_ _

__She trails off, and looks down at the linoleum. The Doctor stares, something uncomfortably close to guilt working its way through her chest. No friends. Except—_ _

__“Well, I’m your friend,” she says, and surprises herself by meaning it. Sure, she needs headache pills just to look at her, and half the time she’s afraid she’s standing next to something that’s about to tear the universe apart, but underneath all that, the Doctor is starting to get the sneaking suspicion that Yaz is just…Yaz._ _

__Normal, and entirely not. A mystery wrapped in an enigma wrapped in a worn leather jacket and a star shirt the Doctor figures is her favorite, cos she wears it so often._ _

__Yaz studies the linoleum for a moment, then looks up and bites her lip. There’s a shy smile on her face, one the Doctor’s never noticed before, and a hint of a flush playing at her cheeks. She looks soft and young and, for once, entirely present._ _

__“Thanks, Doctor,” she says. Her smile grows, slightly. “That means a lot to me.”_ _

__For a moment, the Doctor isn’t sure how to react. Then she grins, loud and meant to change the subject, and gestures widely with her hands. “Well, tea’s ready! What d’you say, we go find something good to watch on Netflix? That’s what you do roundabout this decade, right? Netflix and chill?”_ _

__She can tell immediately by the look on Yaz’s face that she’s got it wrong. Silence fills the space between them, full of something the Doctor is definitely missing._ _

__“Uh, did I get it wrong?” she asks helplessly, once the silence stretches on long enough to turn awkward. Suddenly, Yaz isn't the only one blushing._ _

__Yaz doesn't immediately answer, but stares at her for a long moment, lips parted as if she wants to say something but isn't sure what. Then she shakes her head, and lets out a small laugh._ _

__“Nothing, it doesn't mean anything. But how about we just sit at the table and talk instead?”_ _

__She gestures toward the kitchen table and the Doctor looks to it, then her, and almost goes to ask but then decides not to._ _

__“Great! Love talking, talking’s great. Let's talk.” She takes her cup from the counter and, as Yaz follows suit, makes a mental note to look up Netflix and chill. Seems Ryan was having her on about that one._ _

**Notes for the Chapter:**

> OKAY. so the line 'ghost of a sentence never about to be said hangs in the air', is apparently a carbon copy of a line in the fic i recced which heavily inspired this fic. Now, its been months, probably more than half a year, since i read that fic. I SWEAR, i thought of that line on my own. I was planning on removing it, but didn't, on pain of death from one of my betas. Just know, I really didnt mean to copy.
> 
> And as always, thank you all for the wonderful comments! I love hearing what you guys have to say, seriously, it makes my whole week.


	3. Chapter 3

**Notes for the Chapter:**

> ok i made the mistake of putting a poll on twitter and yall voted for another chapter so here it is YEET

Tea becomes a semi-regular thing at Yaz’s. Sometimes with the boys, sometimes without, and once, on a memorable occasion, with both of her parents, but always it’s at least them, together. They sit, and talk, and usually go through more than one cup, and Yaz finally concedes to tell her what Netflix and chill means.

It’s definitely not what the Doctor thought. 

After a while, the Doctor starts to come away from their meetings with a comfortable warmth in her chest, a sensation completely at odds with her screaming instincts to run. It’s a strange contradiction, but she decides to embrace it because, well, what can she do?

Yaz is her friend. Somehow.

Problem is, the more they meet, the more the Doctor has to ward off the sneaking urge to investigate. Because it’s not a good idea. She _knows_ it’s not a good idea. The very hairs on the back of her neck still raise at the thought, despite the steadily building guilt in her chest that tells her she’s got to look into it. They’re friends now, damn it. Friends help friends out.

But they also don’t stick their noses into rips in the time-space continuum. And the Doctor has done that enough times to learn her lessons, _hard._

Though it doesn’t make much of a difference, because the Doctor isn’t even sure where to start looking. By their twelfth cup of tea, she knows that Yaz had—has—a stuffed bunny named Mister Hoppy, that she likes footy but was too shy to try out for the team, has never been on an airplane, and only—to the Doctor’s horror—eats the cream out of the custard creams, but the Doctor still doesn’t know what to do about her. Yaz still sits in the middle of a nest of fractured time, still wavers in and out when the Doctor isn’t looking. Still occasionally notices things she shouldn’t, despite the Doctor’s considerable subtlety. 

Still, for all intents and purposes, doesn’t make sense.

The Doctor has to get to the bottom of it. She knows she does, senses the probability of it, and rather childishly, doesn’t want to. Therein lies trouble, she's certain of it. The kind of trouble that gives birth to the temporal horrors she’s only known in the Time War. Why on earth would she want to go digging?

She’s ignoring a problem she doesn’t want to exist. That’s the plain of it, and it eats at her, but she lets it, and sits with Yaz, and drinks tea, and when they fly off to see the universe, she wrangles the TARDIS into listening, and ignores her protestations at Yaz’s continued presence. 

She doesn’t want to go looking because, shamefully, she’s afraid of what she might find.

And then of course, the very thing she doesn’t want to find goes finding her instead.

————

The first time it happens, they’re wandering around an enormous, twenty-first century flavored mall. They start the four of them together, but it doesn’t take long until Ryan darts off for the video games, and Graham goes looking for new shirts, leaving the Doctor and Yaz to wander alone, window-shopping high-end brands styled after early twenty-first century fashion.

They have a fun time together, pointing out the more ridiculous imitations, and just as they go off to meet up with Graham and Ryan, the Doctor notices a particularly funny version of 2006 grunge. Grinning, she turns to Yaz to point it out.

Only it’s the wrong Yaz.

The Doctor stares. Fear settles over her flesh, raising goose-pimples. Then she sets her jaw and crosses her arms, her gaze cool. 

“You’re not my Yaz,” she says. Her mouth has gone very, very dry. Yaz just shakes her head, familiar, genial confusion wrinkling her brow. 

“Yeah I am. Just a different timeline. What's wrong with that?”

“What’s wro—” the Doctor mouths silently. Her cool gaze slips into a glare. “Never mind. How can you be here anyway? This should be ripping the universe apart. Even I can’t just shove a whole new Yaz into this timeline. It doesn’t work like that.”

Yaz grins, gives a little shrug. Her eyes, the Doctor notices, are off. There’s something endless, unfathomable there. Looking into them, she gets the sensation that she’s falling.

“Maybe you’re the one in the wrong timeline, Doctor. Or maybe I know a good bit more than you think.”

“I can tell,” the Doctor growls, and her hands fall to her sides, forming white-knuckled fists. She stalks forward until they’re close enough to touch, and even though those eyes are scaring her more by the minute, she forces herself not to look away. 

“Look at you,” she murmurs, and her gaze roam over Yaz’s face, glance down to the shirt she’s wearing—a star, but it’s blue, a jacket but it’s black—then up again. She smiles, hopes Yaz doesn’t see the quaking behind it. “You’re eons off, here. Your timeline—it’s so far off this one even I wouldn’t be able to snatch it. I’m not even entirely sure you’re human.”

“Oh, I am.” Yaz grins, shark-like. It’s not a friendly look. “I just had a little incident, see. So did yours. Or will. Or has. Or is. Have you checked on her?”

“She’s _fine—_ ” the Doctor spits, because all of a sudden she’s not entirely sure. There’s fear blooming in her chest, hot and raw and panicky, and this Yaz is smiling at her, just a millimeter off her Yaz’s sparkling smile, only those _eyes—_

“Doctor!”

Ryan’s voice sounds behind her and she whips around, the fear too-evident on her face, and spots him and Graham a few meters off in the crowd. They’re coming closer, shopping bags in hand, and Graham sees her and gives a little wave, which she doesn’t return. She’s know idea how she’s going to explain that Yaz has simply been—replaced, and she whirls back around, ready to threaten, or conjole, or beg—

“Doctor?” Yaz wrinkles her brow, confused. She’s leaning back slightly, bending under their nearly chest-to-chest proximity. “Are you okay?”

“I’m—” she gapes, jaw working, mouth hanging to the floor. “I—I—”

It’s Yaz. Her Yaz, a small crease of worry in her forehead, eyes dark and warm and confused, and miles off from terrifying. She shimmers, slightly, but she’s there.

“Doctor, you’re worrying me.” Her gaze flickers across her face, down to her chest—they’re nearly touching—and a hint of red appears. The Doctor clears her throat, and takes a step backwards.

“Yeah, I—thought you had something on your face. But it’s gone now,” she adds hastily as Yaz’s fingers go to her cheek. “Must have been a trick of the light.”

“O-okay,” Yaz says, and her fingers lower. They flex uncertainly, then wrap around the handle of the plastic bag in her other hand, the one she hadn’t been holding moments before. “You sure you’re alright?”

The Doctor gulps, and nods, gaze still locked upon Yaz. “Yaz, did you—when did you get here?”

“Huh?” Yaz’s nose wrinkles, then relaxes instead into uncertain humor. “Doctor, you’re having me on, aren’t you? We were only just walking around together.”

“Oh. Yeah. Right.” The Doctor’s head bobs up and down, but she can’t seem to keep the nerves out of her stomach.Yaz herself doesn’t even seem to know what’s happened.

“Yep, sorry, I—got a little distracted!” she says loudly, then realizes how that sounds, and blushes. “C’mon Yaz, let’s get something to eat, yeah?”

She turns, just as the boys arrive, and pushes them all towards the food court. She distracts herself by exuberantly pointing out all the places that’ll poison them, and pretend that it works. But for the rest of the day, she can’t look Yaz in the eye.

—————

She’s had enough.

She steals a minute from Yaz when she isn't looking, plucks it out of a conversation and files it away for later. Yaz doesn't even notice the jolt from the missed moment to the next, or maybe she does; at this point, the Doctor can’t be sure of anything.

She's determined to get to the bottom of this—whatever this _thing_ is, so later, when all the humans are asleep, she goes to her old lab, the one she hasn’t used since before the Time War. It’s chock full of things nobody need use in the absence of temporal powers; small paradox manipulators, vortex samplers, artron particle accelerators, and a thousand more ancient pieces of lab equipment. But she ignores them all, heading straight for the temporal microscope. She slides the missing minute inside, and cranks it up until Yaz’s timeline is magnified a hundred times, big enough to make out every tiny blip and possibility. 

And once she sees it, she understands. Sort of.

It's a mess, first of all. The Doctor has borne witness to millions of timelines, even dissected a fair few back in the Academy, and she knows how one is meant to look. Beautiful and spiraling, looping off in an endless web of chances that may or may not happen. Never joining, never intersecting. Ideally. Or at least not without great care.

Yaz’s timeline, or at least this segment of it, is just…all piled up on itself, as if somebody had taken a spider’s web and clumped it into a ball. She looks at it and wants to wince, because it's _painful_ to see; ragged and torn and layered together in ways it most definitely shouldn't be, and all she can do is stare and wonder what the hell happened.

“This is…revealing,” she mutters to herself, and reaches out to shut the machine off. The problem is, she's not entirely right, because it _isn't;_ it tells her nothing about the origin of the problem, only that it exists. Which she already knew.

Though it is sort of nice to have it in print. Proven.

“Well, gotta start somewhere,” she says, then laughs hollowly, because she doesn't think she could find a start or an end to this mess if she tried. 

“Right.” She removes the minute from the machine, stuffs it into a temporal pocket, and turns away, hands shoved into her pockets, eyes glued to the dusty floor, face screwed up in thought. There are a thousand ways she could handle this, probably, half of them badly, and none of them likely to provide any firm clarification, but she can only see one immediate, obvious answer. Much as she doesn't want to do it.

She has to talk to Yaz.

—————

She corners her alone in the console room two days later, after sending Graham and Ryan off on an elaborate errand to find a certain wrench for the console which doesn't exist. She directs the TARDIS to lead them in circles for about fifteen minutes, and figures that's enough time to sit Yaz down and explain the whole incomprehensible situation.

(She doesn’t want to. She really, really doesn’t want to, but it’s starting to look more and more like a problem she can’t avoid, and it makes her skin crawl, but it has to be done. Facing the nail on the head—or, no, that’s not it. Well, doesn’t matter. Human turns of phrase are rubbish for something like this, anyway.)

Yaz, unsurprisingly, catches on to her ruse. She's leaning up against the console by the time the Doctor waves the boys off, and when she turns around, hand uneasily palming the back of her neck, Yaz has her arms crossed and a frown on her face.

“Why do you want to talk to me?” she asks, narrow-eyed. “Is this about those things you won't explain?”

“T-things?” the Doctor stutters. She's more nervous than she should be, she thinks, considering she's facing down one of her friends. Her friend, who might be the epicenter of a universe-rending temporal anomaly. 

Maybe she's right to be a little nervous.

“Yeah,” Yaz says, and then clarifies, “The thing on the train. And after the funeral. Those— _things_ you keep doing, only nobody notices except me, I think.”

Her tone drops uncertainly on the last word, and she eyes the Doctor, looking like she thinks she’s gone too far. Then, when the Doctor doesn’t say anything, she draws in a breath, squares her shoulders, and keeps going.

“I know there’s something wrong, Doctor. You keep looking at me when you think I’m not paying attention, like I’m—like there’s something off. So what is it? What’s so wrong you won’t even tell me?”

She looks scared now, openly so, and all the Doctor can think is that she has a right to be. Only it’s not fair, it really isn’t, because as far as the Doctor can tell—not that she can tell much—whatever is going on with Yasmin Khan is not her fault.

Or she doesn’t think it is. She’s going to look an awful fool if she’s wrong.

“Yeah,” she says after a long second stretches between them. “It's about those. And you, really.”

She pulls a hand out of her pocket, gestures vaguely around the room. “I'd ask you to sit down, but, well…”

Yaz follows her gaze, sweeping across the room, and shrugs, juddery, nervous. “I'm fine here, thanks.”

“Right. Okay.” The Doctor swallows, and wonders what the hell she’s meant to say. Where is she even supposed to start?

But Yaz is staring at her, waiting and worried, so she shoves her hand back into her pocket and thinks, with just the tiniest bit of caustic irony, _might as well start at the beginning._

“Let me explain to you about the way I see time…”

Yaz takes it well, all things considering. The Doctor does leave a few things out—mainly the unsettling encounter in the mall, which she still hasn't managed to shake from her mind’s eye—but gives her all the important bits, ending, a little guiltily, on the illicit experiment she'd done with the stolen piece of time.

“You— _took_ a _minute_ …from my timeline?” Yaz asks. She looks unsure whether to be confused or angry. “Isn't that—shouldn't I have—?”

“Noticed?” The Doctor jumps in quickly. She shakes her head. “Nah, it’s not dangerous. And it's borrowed, really. I returned it.”

“ _Returned_ it—” Yaz stares in disbelief. “I…okay. But I don't get it. What's—why am I wrong? Can't you put me back?”

The Doctor winces at the question, at the squeak of apprehension on the end of it, and runs a rough hand through her hair. “I…listen, Yaz. There's no putting you back. You _are_ this way, were like this even before I met you. I only noticed it, that's all.”

“No way,” Yaz says. Her arms are still drawn tightly across her chest, her shoulders in a stubborn set. The picture of fearful obstinacy. “That doesn't make sense. I never noticed anything different before. I never _saw_ things like what you did, before…”

The Doctor shrugs, and gives her an apologetic smile. “Bet you never met someone who could do them.”

Yaz stops, mouth open to respond, then snaps it shut. She uncrosses her arms, and drops her hands to the console, fingers curling around the underside of the dashboard. For a moment, she surveys the Doctor.

“So…what does this mean?”

The Doctor chuckles, a little desperate. “If I knew, I swear I would fix it.”

“Does it need fixing?” A glimmer of hope appears in her eyes. It's almost painful to see. “I mean, it ain't hurting me, is it? I don't think it's hurting me.”

“I—” the Doctor thinks back to the mall, and those dark, frightening eyes. “It's best to take these things with caution. Temporal matters…you always need to be careful. I've learned that the hard way.”

“Oh.” There’s disappointment in her voice, short and bitter, and the Doctor can't blame her. “Well, I don't see what I can do about it.”

“Nothing,” the Doctor says quickly. Yaz’s head jerks up, confusion flashing across her expression. “I mean…you can't do anything. But I'll keep working on it, yeah? I won't let you down, Yaz. I promise.”

She can't keep her gaze from falling to Yaz’s trainers on the last word. It's a slightly hollow promise, not because she won't keep it, but because she's not sure she can, and even though she knows it ruins the whole speech, she can't say it looking Yaz in the eye. The words _what if I can't?_ keep running around her head, and she's irrationally afraid that if she looks up, Yaz might see them on her face.

“I know. Don't worry, I trust you.” 

The Doctor can hear the fear in her voice, thick as syrup, but senses the brave smile trying to muster through as well. A grin of her own twitches at her lips. Brave Yaz. Proper brave, even though she's scared. She gets the sudden urge to sweep her into a hug, but stifles it. Instead she puts on her own brave face, and looks up to meet her gaze, pulling on what she hopes is an encouraging smile.

Deep enigmatic eyes watch hers, a small smile sitting on her lips. Yaz is wearing a footy uniform, dark blue shorts and a white, wick-sweat top, SHEFFIELD KNIGHTS printed across the chest. She's got her thumbs hooked into her waistband, hair in a braid, one cleat toeing a hole in the floor.

“Really Doctor?” Her expression is affably amused. “We were just about to go on the field. This better be good.”

The Doctor quirks an eyebrow. Her hearts are pounding. “Yaz plays footy?”

Yaz takes a quick look around, and her eyes widen. “Oh, am I—?” 

She looks to the Doctor and grins, contrite. “Guess I got confused again, didn't I?”

Just looking at her is a headache waiting to happen. And her _eyes…_

The Doctor blinks, once, then again in surprise. Yaz is looking at her, nervous and confused, her knuckles white gripping the edge of the console. The footy uniform is gone.

“I mean it. I do trust you,” she says. “You don't have to look so surprised.”

“I’m not—” no, she definitely is. She closes her mouth, and gives a relieved smile. “Thank you. Yaz. I promise I’ll do everything I can.”

She just doesn’t know what that is, yet.

**Notes for the Chapter:**

> what's wrong with yaz? who knows? (i do, sort of). jk, i swear i actually know whats going on with this fic. like, mostly.


	4. Chapter 4

**Notes for the Chapter:**

> the plot? thickening? maybe. perhaps. sort of. anyway, you guys have given me the most amazing response for this story, and I'm seriously so thankful. I mean legit, you guys are great. I hope I continue to not disappoint, and that the payoff will be worth it (there is a payoff, dw). in the meantime, enjoy :))

As it turns out, ‘everything she can’ boils down to ‘not much’, and even when she finally makes a breakthrough, it's not she who makes it, but Yaz.

Only it's not _Yaz._

“Can I see it?” Yaz asks, after a few weeks of hard work and no results. The Doctor almost refuses. She’s at the end of her rope, biting her tongue to keep from screaming in frustration, and Yaz catches her just as she’s about to head into the lab to conduct an undoubtedly useless experiment. It takes all her willpower to keep from snapping a harsh _no._

Instead she turns to Yaz, a weary smile on her face. “See what?”

“My timeline,” Yaz says. Her eyes dart nervously to the jar the Doctor holds in her hands, into which the Doctor has stuffed a small pocket universe. She opens her mouth as if she wants to ask what it is, but then seems to think better of it. Instead she shifts nervously, the rubber soles of her white trainers squeaking against the metal floor. In the silence, the noise is apparent.

For a brief second, the Doctor hesitates. Again it flashes across her mind to say no, not because she’s frustrated, but because she’s not sure it’s a good idea. She’s not even sure Yaz will be able to comprehend what she’s looking at, if she shows her. And if she does manage to understand, to see—well, it’s not a pretty sight.

But then, the Doctor reminds herself, Yaz is very brave.

Her smile is fading slightly, just thinking about, it but she forces it back in place. 

“Sure,” she says, and shifts the pocket universe under her arm. “Why not?”

“Don’t touch anything,” she warns as she leads Yaz into the lab, even though that's more Ryan's bag. 

“I won't,” Yaz promises, though she's already bending over the paradox manipulator, nose almost touching the controls. She's looking at the equipment with interest, but not a hint of understanding, which only lends to the Doctor's confusion. It would be easier if she were some kind of alien in disguise. A time parasite, maybe. Not that such a thing exists, but the Doctor isn’t willing to rule anything out at this point. 

The Doctor watches her for several moments, until Yaz looks up, and their eyes connect. The Doctor clears her throat and whirls around, sliding the minute into the temporal microscope.

“Alright,” she says, and begins to crank up the magnification. “Ready to see?”

Yaz doesn't answer until the Doctor looks back and finds her staring at the minute, still too small to make out. She catches the Doctor’s eye and nods, then sidles closer, fidgeting with the hem of her shirt. In the quiet between them, the Doctor can just barely make out the thump of her heart. It’s rapid and scared, like a caught bird’s. 

She watches without comment as the Doctor magnifies the slide, until she finishes and steps back. Then she points. “Is that it? The gold stuff?”

The Doctor grimaces, because ‘gold stuff’ is not the word she’d use to sum up the elegant beauty of a timeline. Not that this one is elegant or beautiful. She decides to let it go. “Yep. All that…gold stuff there, those lines, sort of like webs? That’s you. Or, a piece of you, in time. See how it’s all scrunched up?”

Yaz steps closer, squinting. “Huh. Yeah. It’s not meant to look like that, is it? All mushed up together.”

“Yeah—no, no it isn’t.” The Doctor shakes her head, and steps up beside her, hands jammed into her pockets. She points her chin to the slide. “And see those bits, those ends? Those shouldn’t be there. They look almost…frayed, near as I can figure. Chewed up. Only I’m not sure why.”

Once again, frustration crawls up her throat. She feels the urge to kick it away, or to kick _something,_ only last time she did that in the lab, she discovered nothing but a bruised foot. So she swallows it back and stares at the slide, waiting for Yaz to say something, anything. It occurs to her that she’s actually taking this rather well, or at the least, she’s very good at faking. 

“Hang on, haven’t we looked at this one already?”

“Huh?” The Doctor turns, confusion scrunching her nose. “We haven't—”

Then she trails off, realization sinking in. Her eyes travel up and down, searching for a difference, something, anything—

It's subtle, this time around. Yaz is dressed nearly the same, right down to the intricate plait of her hair. She's got her brow crinkled in confusion, a frown tugging at her lips, and when she turns to the Doctor, there's nothing in her eyes to indicate she's not the right one.

Except for her faded blue trainers.

Ah.

“You’re not my Yaz,” the Doctor says, hands balling up the inner cloth of her pockets. “What'd you do with her?”

Yaz gives her a strange look. “Doctor, what are you talking about?”

It's enough to give the Doctor pause. Her eyes run over Yaz again, taking in her almost identical appearance.

“Oh, you’re very close,” she says quietly, possibly to herself more than Yaz. Then she clears her throat, and speaks up. “What are you, a single timeline away? Got blue trainers instead of white in the shop?”

Yaz takes an uncertain step back. “Doctor, I've actually got no idea what you're talking about.”

“No, course you don't,” the Doctor sighs, and rubs her chin, still staring. “How can you? I'm beginning to think, Yaz, that none of this has to do with you. You're just the victim.”

“That's what you said before,” Yaz says. She hooks her thumbs into her jacket pockets, and shifts her weight, nervous. “Weeks ago, remember? We had a conversation just like this.”

_Maybe in your timeline,_ the Doctor muses, but she doesn't say it aloud. Instead she says, “No, sorry, don't recall. What else did I say?”

Yaz is looking at her like she might be cracked. Well, maybe she is. “You said it looked familiar. Like it reminded you of something, but you didn't know what.”

The Doctor is starting to think she likes this Yaz’s timeline better than the one she's in right now. It's certainly a lot more useful. 

“So I did!” she says, and bursts into a toothy grin meant to reassure. She spins towards the slide, and takes another look, conscious of Yaz’s gaze on her back.

Only she doesn’t see it.

Oh, the Doctor desperately wants to kick something right now. Possibly a table leg.

“Doctor?” Yaz’s voice sounds behind her, unsure. Apprehensive. “You okay? You look like you’re about to murder someone. You know there’s no rush, yeah?”

She knows even before she turns around, but her eyes flick down to those trainers just to make sure. They’re white, the rubber soles slightly grayed from the dusty floor.

“Right,” she says, and takes a step back, though her eyes remained fixed upon the minute. “No rush.”

————

The next day, Yaz decides that she wants to help, which is a pretty bold proposition, because the Doctor doesn't need it. Nor is she keen on the headache that tags along with her as well.

So for once she dredges up some guts and says no. That it's not a good idea, she works better alone, and besides, doesn't Yaz have better things to do?

Turns out she doesn't. It also turns out that she's persistent in a passive aggressive manner that the Doctor decides she doesn't particularly take to. She discovers this the day after she turns Yaz down, when she arrives at the lab and finds Yaz already there, wearing pajamas and sleep-tousled hair, yawning in slippers. She looks as if she's just gotten out of bed, which is likely. The Doctor saves most of her investigating for when the fam is fast asleep, specifically to avoid awkward situations like these.

“Yaz,” she says, and doesn't bother to hide the unenthusiasm in her voice. “I thought you were asleep?”

“Yeah. I asked the TARDIS to wake me up.” Yaz shrugs, and reaches up one hand to rub sleep out of her eye. Standing there, she looks like a kid waking up on Christmas morning. It'd almost be cute, if the Doctor didn't want her to be there. 

“Hmmm.” The Doctor casts a swift glare at the ceiling. “But you know I meant what I said, yesterday. I'm sorry, but I don't need an extra pair of hands.”

She turns to the door as she says this, hoping to stem any further argument.

“Yeah, but—” Yaz pipes up. She sounds a little desperate, enough to make the Doctor pause. “I could—I dunno, sit and watch? Hand you things? I won't be in your way, I swear.”

“Er—” the Doctor hesitates. She's got one foot in the door, and knows that once she swings it shut behind her, the TARDIS won't let anybody else in, on her command. Only Yaz is standing there, and, when the Doctor looks back, she's biting her lip, her face a mess of uneasy stubbornness. As if she’s afraid the Doctor is going to say no. As if she’s prepared to stand there until she doesn’t.

The Doctor sighs, and turns to face Yaz.

“Yaz—” she rocks back on her heels, and her hands, with nowhere to go, come together to wring, awkwardly. “Why do you want to? It's boring, I swear, and it’s not—no offense—as if I have the time to explain what I’m doing. You’ll just be sitting there, watching me do things you don’t understand.”

If she’s a little harsh, she can’t help but think that’s for the best. It stings a little, sure, but it’s worth it when she thinks about the headaches she’ll be saving herself from. She’s already getting one right now, swimming just behind the eyes. It’s distracting, and that’s the last thing she needs.

But Yaz just nods, chin jutted at a stubborn angle, and says, “I don't care. It's my timeline, isn't it? I should get to know what goes on with it.”

“I—” The Doctor almost groans. Almost. She’s 3000 years old, fortunately, and with enough practice at hiding emotions to catch herself at the last second, schooling it instead into a weak smile—barely a twitch of the lips. And when she speaks, she tries, hard as she can, not to let any of her frustration through.

“But why? You trust me, don’t you?”

She hadn’t meant it to sound like an accusation, but Yaz draws back in surprise. 

“’Course I trust you,” she says. “S’not about _that._ Only it’s just—you dropped this thing on me, alright? Telling me I’m _wrong,_ and you don’t know why, even though I can’t tell myself, and then you just—say you’re gonna fix it and go off, and I’m stuck sitting here, twiddling my thumbs, and I can’t—I can’t—I have to do _something,_ Doctor. I’m going mad.”

She says it all in one big rush, then draws in a breath and holds it, waiting. Her hands hang loosely at her sides, fingers twitching at the seams of her pajama tops, as if she’s dying to ball them into nervous fists.

The Doctor just stares at her. Dimly, she registers her own look of surprise—so much for hiding her emotions—but more than that, she just feels bad. Ashamed, because while she’s been locked up in her lab, trying to figure out what the hell is wrong with Yasmin Khan, she’d forgotten to take a look at the human under the problem.

And now she’s looking, and she doesn’t like what she sees. Yaz’s hair is a mess, which the Doctor could attribute to sleep, only it looks like she’s not getting any. There are dark circles under her eyes, a dullness to her gaze, and she’s starting to think that the twitch of her fingers is more than just temporary nerves.

Yaz looks a mess. And the Doctor hadn’t even noticed.

“I—” she stops, swallows once, then tries again. “You’re right, Yaz. You deserve to know what I’m doing. And I’m sorry I haven’t noticed.”

“Huh?” Yaz’s head jerks up, her eyes widen. A faint blush appears on her cheeks, then she shakes her head once, quickly. “Oh no, that’s—you don’t have to apologize, Doctor. I just want to know what’s going on. I can’t stand sitting here being useless.”

“Me neither.” The Doctor smiles, and this time she makes sure to mean it, because she figures Yaz deserves that, at least. An honest smile, even if the Doctor hasn’t been the greatest friend, lately. Too wrapped up in the mystery, rather than the person.

The words of her promise ring dimly, in the back of her head.

Without looking, she reaches behind her and turns the door handle, pushing it open, then gestures for Yaz to go ahead. “Ladies first?”

Yaz gives her a funny look, but then smiles. “Old habits?”

The Doctor grins. “Old habits.”

————

Yaz’s presence turns out to be an unexpected comfort in the lab. She doesn’t say much, but she’s there, and despite the dull ache behind her eyes that the Doctor has resignedly learned to live with, she finds it surprisingly pleasant to work with company around. Yaz gives her an audience, even if the Doctor doesn’t necessarily need one, and someone to toss ideas to, even if Yaz can’t necessarily provide any of her own.

And okay, the Doctor can recognize she’s a bit of a grump when working on something, in any regeneration, but around Yaz, she’s…not. Or rather, when something goes wrong, and she wants to bring her hand down on the table, or let out a string of curses in Gallifreyan, she glances towards Yaz, watching her with those dark, understanding eyes, and holds her tongue.

She’s not sure why, since she’s pretty much snubbed her for weeks—possibly months—on end, but for some reason, the Doctor doesn’t want to look bad in front of Yasmin Khan.

Sometimes, it’ll be the wrong Yaz for a little while. She’ll slide out, without the Doctor even noticing, until she looks up and notices that this Yaz is wearing jeans, when before she was most definitely wearing pajamas. Or she’ll have her hair in a bun, rather than tumbling around her shoulders. Subtle things, most of the time. And sometimes not.

Once, the Doctor glances over to Yaz, and nearly jumps out of her skin to see an enormous scar running from her hairline to her chin. Long, jagged. Fairly new, from the looks of it. She gapes, then shudders and pretends she hasn’t seen, and doesn’t say anything. She risks looking up several minutes later, and is relieved to see her own Yaz back in place.

Sometimes, they talk. Not often, because the Doctor gets far too absorbed in her work to carry on any real sort of conversation, but it happens. The Doctor will ask a question out loud, usually rhetorical, and Yaz will answer with something surprisingly insightful, and it’ll snowball from there, until the Doctor finds herself knee-deep in a discussion on dimensional physics. She’s never sure how much Yaz understands of the conversations that take place, but she listens attentively anyway, often with a small, indecipherable smile on her face. A sparkle in her eyes, which the Doctor is never sure what to make of.

She opts to ignore it, mostly. One problem at a time.

Then one day, Yaz asks about the Time War.

Well, not exactly. But she leads into it, if only by accident.

“Doctor?”

“Hmm?” the Doctor doesn’t look up. She’s crouched with a couple screws between her teeth, trying to patch up a section of her paradox manipulator, and she’s at a particularly tricky bit. She almost doesn’t catch the next question.

“Do you know what you’re looking for?”

The Doctor pauses, sonic just touching the panel she’s meant to be replacing. Then she brings a hand to her mouth and spits out the screws, before settling back on her heels and looking up. Yaz is perched on an empty worktable, trainers swinging lightly, fingers curled loosely around the edge of the table

“You mean, have I found anything?” she keeps Yaz’s gaze, steady for a moment, then looks down to carefully deposit the screws in her pocket. She hears Yaz inhale, on the brink of asking a question, before letting it out again.

“Sort of,” she says, the hesitates, biting her lip. “I mean, not exactly. It’s just—well, do you have an idea? Or are you just poking around until you find something?”

The Doctor doesn’t miss the slight reproach in her tone. She frowns, affronted. “Oi, I do know what I’m doing, thanks very much.”

Yaz’s lips twitch into a smile, but skepticism still hangs over her brow. “Okay, but do you know, then?” she repeats. “What it is you’re looking for? Because usually you never say anything about that. Don't talk much, really.”

The Doctor smiles fondly, and leans back on the floor, planting a hand to steady. “Yeah, I do get caught up, don't I? And uh, to answer your question, I really don't. I'm sorry. I’ve never seen anything like this before. At least, I don’t think I have.”

“Don’t _think_ you have?” Yaz leans forward, hands tightening around the edge of the table. “What’s that supposed to mean?”

The Doctor winces, and her eyes drop the Yaz’s shoes. “Nothing. It’s just what I said. It doesn’t look familiar.”

_Though it should,_ a sly voice at the back of her mind whispers. She frowns, because she’s been thinking about that conversation ever since, trying to decipher what that other Yaz had meant. How was it supposed to look familiar? For the hundredth time, something tickles at her memory, but when she grasps towards it, it slips away.

When the Doctor doesn’t answer, Yaz leans farther forward, catching herself just before she falls. Her legs swing under the table, and the Doctor watches them, rather than her.

“Why won’t you tell me?” she demands. Her brow has begun to crinkle with worry, trepidation. “What, is it that bad you’re too scared to admit it? Have you found something, and you just don’t want to—”

“No, I haven’t found anything,” the Doctor cuts her off, soft but firm. Yaz stops, but the Doctor can feel her gaze upon her, even without looking up.

“Yeah, but?”

“But?” the Doctor looks up, and Yaz shrugs.

“Yeah, but. But, what don’t you want to tell me? Why’d you go all quiet?”

The Doctor purses her lips, and her gaze falls back to Yaz’s shoes. She watches them for a few seconds, debating. 

Finally, she says, “I wasn’t lying when I said I haven’t found anything. But I have seen…things, that your condition reminds me of. Monsters, and machines that could manipulate time on an enormous scale. A horrific scale. You wouldn’t be able to wrap your head around it if I told you. They don’t exist though, thankfully, which is why I didn’t tell you. Because I didn’t want to scare you for no reason.”

Yaz is silent when she finishes, and the Doctor doesn’t look up. Instead she watches Yaz’s shoes, which are now still, and wonders if she’s missing something. Because those creatures—the Nightmare Child and the Should-Have-Been King, the Neverwheres—are all gone now, locked away with the rest of the Time War. But now that she’s thinking, there is something naggingly familiar about Yaz’s timeline, something that puts her strangely in mind of—

“If they’re all gone, where did you see them?”

“Huh?” the Doctor’s head jerks up of its own accord, and she blinks, then refocuses on Yaz. “See what?”

“Those things,” Yaz prompts. “How can you have seen them, if they don’t exist? Actually—” she frowns— “Yeah, hang on. That doesn’t make any sense.”

For a beat, the Doctor stares at her, uncomprehending. Then, she realizes, and laughs. “Oh, sorry. I’m forgetting my tenses, aren’t I? I meant they did exist, once. But now they never did. It’s a timey-wimey thing, you see?”

By the expression on Yaz’s face, she doesn’t. Her frown deepens, her nose crinkling. “No, you’re still not making sense. How can something have existed once, and then never existed at all?”

“Umm…” she flails for an answer. The obvious one, the truthful one, is a very deep and painful topic she’d rather not get into right now, or ever, but Yaz is watching her with curious, insistent eyes. Waiting. “Um. It’s…that’s a difficult thing to explain, Yaz. And it involves a lot of rather unpleasant memories.”

She’s hoping that will dissuade her. Yaz is a kind soul, she’s found, and one who usually takes the hint. Only this time, she doesn’t. She hesitates, then sets her jaw. “I’d like to hear about them. If you don’t mind.”

The Doctor sort of does, but Yaz is employing one of those human politeness tricks, the ones she’s never been good at. Now she can’t refuse without looking rude, she’s fairly certain, and she gets pegged as rude often enough, particularly in her last regeneration. So she sighs, a little dramatically just to drive the point home, and says, “Well, if you’re sure you have time…”

“We’re in the TARDIS, Doctor. Floating through the time vortex.”

The Doctor’s lips drop into a frown. “Right. Forgot about that bit. Okay, then, let me think.”

She leans back on her hands, braced against the dusty floor, and purses her lips together. “Let me start at the beginning. With my people. You see—”

She doesn’t mean to wade in too deep, but before long she’s up to her waist. It’s a lengthy topic, and one that requires far too much background knowledge for one simple conversation. But after a while, Yaz appears to get the gist. Her eyes grow wide and she falls almost completely silent, making only the occasional nod or murmur of horror throughout.

“So you think it might be related?” she asks, once the Doctor winds down into pensive silence, a familiar pit sitting in her stomach. It always appears when she talks about the war, or even thinks about it, no matter how old she gets. Some things, she supposes, you never leave behind. 

“The Time War is locked away, Yaz. It can’t reach this universe.”

“I know, but it could be something similar, couldn’t it? All those tactics you talked about, messing with timelines and things, couldn’t something be doing that to me? Maybe—”

_“No,”_ the Doctor answers harshly, and only too late realizes her tone. Yaz flinches, and she tries to reel the next few words back in. “I mean—Yaz, there isn’t a single creature left in the universe with that kind of power. Except my people, and they’re locked away at the end of the universe. And anyway, why would they want to do something like that? It doesn’t make any sense.”

Yaz shrugs, and looks to the ground. Her trainers begin to swing again, back and forth, back and forth. “I dunno. Maybe to get to you.”

The Doctor gives a hollow laugh. “They don’t hate me that much, Yaz. Well, they did once, but I’ve made up a few things. Sort of.”

_And I didn’t even know you,_ she thinks, though the thought makes her immediately guilty. _I didn’t even care, I would have dropped you back in Sheffield if I could. I almost did._

“Okay.” Yaz is silent, so the Doctor is too. They stay silent for several moments, then she hears a quiet exhale, the only sound besides the thump-thump of her two hearts.

“I’m sorry, Doctor. That you had to go through that.”

The Doctor looks at Yaz in surprise. “You don’t have to be sorry, Yaz. It’s long over, anyway.”

Yaz looks at her, and there’s something unusual in her eye, something the Doctor doesn’t oft see in humans. A grief that’s not her own.

“Yeah, well I am, anyway.”

The Doctor doesn’t know what to say, so she just says the first thing that comes to mind. “Thank you.”

————— 

That night, the Doctor dreams about the Time War. She dreams of Daleks screaming their victory at the fall of Arcadia, even though she knows, _she knows,_ it wasn’t a victory in the end, and she dreams of thousands of planets burning, and children sobbing with fear, and whole galaxies eaten alive by battle. She dreams of the Time Lords, wiping it all out to start the battle again, because they didn’t like how it went the first time. 

And as always, she dreams of the monsters. She dreams of the Could’ve Been King, with his army of Meanwhiles and Neverwheres, and the Horde of Travesties, which nearly swallowed up her own planet, and she dreams of the Nightmare Child, which is the worst of all, because he was the one she helped create. 

And in the last dream, the monsters all take Yaz’s face, and laugh and laugh and laugh, the same way she laughed in their faces to cover her own fear, and she wakes sweating to the image of the Nightmare Child leering over her, which is absolutely ridiculous because the Nightmare Child had no face. Only a ravenous hunger, and a childish, sullen disposition, with which it would destroy worlds.

She sits straight up in her own bed—an unusual circumstance, and one she’s definitely not repeating—and stares around the room, at the half-hidden shadows. She thinks of the Could’ve Been King, of the Horde of Travesties, and trembles.

“Just a dream,” she whispers to herself, and pulls the blankets up high. “Just a dream.”

Fifteen minutes later, she’s fully dressed and in the console room, working on repairs.


	5. Chapter 5

**Notes for the Chapter:**

> ok I'm a bit late for this chapter, but better late than never, yeah?

Two weeks into her (mostly) silent observation of the Doctor’s work, Yaz discovers that the Doctor takes headache pills. And it’s the Doctor’s fault, mainly. She’s grown used to Yaz’s comforting presence, her quiet breathing and occasional comment, oft-unanswered, sunk into the background like soothing, wordless music. 

So it’s with nary a second thought that, on a particularly exhausting day, when her head is thudding dully without reprieve, she slides a container of pills from her pocket and pops one, two into her mouth.

Actually, she pops one into her mouth, only to freeze, when she turns slightly and catches sight of Yaz’s baffled expression.

“What?” she asks, and gulps down the tablet. “Something on my face?”

Yaz doesn’t take the bait. Instead she points to the container, still held in the Doctor’s hand. “You take pills?”

“Uh—” the Doctor glances down, then winces. No ready lie comes to her mind because, well, she’s just been caught. With her hand in the cookie jar, so to speak. “Yeah, I do, actually. S’not a big deal though. Nothing to worry about.”

But she can tell by the look on Yaz’s face that it definitely is. To her, at least. Her lips curl into a frown. “You never told me that. Us that. What do you take them for? Are you okay?”

The Doctor shoves the container back into her pocket and tries to wave it off. “Oh, yeah, I’m fine. Really, Yaz, it’s nothing to worry about. I get headaches, that’s all. Time Lords aren’t above pills, you know. Uh, except for aspirin. Don’t give me that, or I’ll die.”

“Um, okay.” Yaz is still staring at her, and is very clearing not letting the issue go. Her frown is growing deeper by the second. “Are you sure it’s okay? Maybe it’s a light thing. Me mum had—”

“No, Yaz, it’s not a light thing.” The Doctor laughs, and quickly, before Yaz can see, turns away and chucks back the second pill. She swallows it dry, and pretends to examine the minute she had just finished dissecting. “It’s uh—well, it’s not important. Not an issue, is what it is.”

“Really?” Yaz asks. “Is that why you didn’t want me to see you take the second pill, then?”

The Doctor freezes. Then, slowly, she turns around, and spreads her arms wide, her face the picture of innocence. “What pill?”

Yaz slides off the table she’s sitting on, and stalks forward, hands balled into stubborn fists. When she gets a step or two away, she pulls up short, and puts her hands on her hips. Her lips are pursed, brow furrowed. She looks like a mum, about to deliver a lecture. 

“Doctor,” she says, and she sounds like one too. “Tell me.”

And the Doctor is starting to feel like a petulant child. She puts her hands on her hips too, and strongly resists the urge to stick out her tongue. “No. I don’t have to.”

(And in the meantime, she’s wondering, when are those darn pills going to kick in? Yaz is fading in and out, like she always does, and it’s been a rather sleepless day. The Doctor could use a clear head, _for once._ )

Yaz is full-on glaring now. She takes a step closer, enough for the Doctor to notice the height difference, and take some immature pleasure in the fact that she’s taller.

“Tell me. Tell me, or I won’t leave you alone til you do.”

The Doctor raises an eyebrow. “Oh, really? And how do you expect to do that?”

Yaz is already opening her mouth to retort, but at the Doctor’s response she stops short, baffled. “Huh?”

The Doctor sweeps a cocky hand across the laboratory. “Well, if you haven’t noticed, Yaz, we spend most of our time together. Reckon you’ll have to try a little harder than that to get the truth out of me.”

It’s funny, too, because it’s only when the Doctor says those words that she realizes the truth of them, and she can tell by the look in Yaz’s eyes that the revelation is a new one for her as well. She takes a step back, cheeks reddening—the Doctor has _got_ to get to the bottom of that—and mumbles, “Yeah, well I can be right annoying if I want to.”

“Like I said,” the Doctor grins. “You’ll have to try harder.”

Yaz huffs, and the flush on her cheeks deepens. “Why won’t you just tell me? If it’s not a big deal, there’s no reason to keep me in the dark.”

“Well…” The Doctor hesitates. She’s not keen on telling Yaz the problem, precisely because Yaz _is_ the problem, and she’s pretty sure it’s not polite to divulge such a thing to her face.

And besides, she’s slightly afraid that if Yaz knew, she would leave. And the Doctor, strangely enough, has grown to enjoy her company. She’s a calming presence, when she’s the right Yaz. And even then, the wrong Yazs don’t exactly _bother_ the Doctor. 

They just make her skin crawl, a little.

“Because it’s not important,” the Doctor replies, and then sees that such an answer is not going to stem the problem. Of course it won’t; Yaz is not the kind to take such a statement at face value, especially when the Doctor is involved. Which is a bit odd, now she thinks of it.

Yaz is looking at her, unconvinced, so the Doctor tries to lay it on thick. “Really Yaz, it’s not. It’s the stress, and the working long hours, and—” No, those aren’t good reasons either, because now Yaz is looking increasingly worried. She tries to change tact. “But it’s not because of the work! I had them before, actually, so it’s not related to that. Actually—”

“What is it related to, then?” she’s got her hands on her hips still, but there’s no bite, only obstinacy as she shifts her weight to one side. “If it’s not the work, and you’ve had them before—”

“It’s—” the Doctor flails. “It’s not because—”

She stops herself, but it’s too late. Yaz’s eyes widen, and her hands drop from her hips. “Oh my god. It’s me, isn’t it? You said before, that I look different. Is that why? You can barely stand to look at me?”

“I—no, I—” but she’s found out, she can read it in Yaz’s face. The Doctor opens her mouth, realizes it’s pointless, and sighs, shoulders sagging. 

“Okay, I—maybe,” she admits, then shoots her hands up in front of her, halting whatever Yaz is about to say. “But it’s not _you,_ Yaz! It’s whatever—whatever’s around you. This thing—” she gestures widely to the general space Yaz stands in— “it’s the problem, see?”

But Yaz takes a step back, red-faced horror creeping across her expression. “That’s why you didn’t want me in the lab, isn’t it? And why you never treated me like—like you treated Graham and Ryan, isn’t it? You were always ignoring me, and I thought—I thought—”

“That I didn’t like you?” the Doctor winces, because it’s just a tad too close to the truth, though of course her dislike was never directed at Yaz herself. Or, then again—well she’d never given her the chance, had she? Not at first, at least. 

Hurt flashes deep in Yaz’s expression. “Yeah. That you didn’t like me.”

“Oh, but Yaz—” the Doctor is trying desperately to come up with something that’s not a lie, because she has a feeling Yaz will read right through it. “Yaz, it’s not—I never didn’t like you. I just—I was a bit scared, that’s all.”

_“Scared?”_ Yaz stares at her in disbelief. “Of me? Are you crazy?”

“I’m starting to wonder,” the Doctor replies dryly, then realizes that’s not the tone she should be striking, at the moment. Quickly, she backtracks. “No, I mean—listen, Yaz. None of this is your fault, you know that, right?”

“Yeah, I know.” Yaz has her chin set, her expression stiff with anger, or hurt, or both. “You’ve told me that before.”

“That’s because it’s true,” the Doctor insists. “I meant what I said. And I’m sorry, Yaz, because I know I haven’t been the friendliest. Shutting you out of the lab and—” She thinks back, briefly, to all the times she snubbed her, all the times she prayed she would leave. “—and everything else. But I swear, I’m just—”

“Trying to make it up to me?” Yaz crosses her arms. 

“No.” The Doctor says, then pauses, because really, what had she been trying to do? She’d only invited herself over for tea because she’d felt bad, only begun to investigate, because—

No, that wasn’t it. Guilt may have propelled her original intentions, but she’s long past that now. She’s not helping Yasmin Khan because of a promise, anymore.

She’s helping her because she cares.

“I care about you, Yaz,” she answers, honestly, and prays that Yaz will read the truth in her expression. Yaz is watching her, scrutinizing, as if she’s not sure what to believe. 

“Really?” 

It’s the tone that gets her. Plaintive and hopeful and desperate all rolled together, as if she so badly wants to believe such a thing, but isn’t sure it to be true. And the Doctor just stares, mouth hanging, because _really,_ had she been that awful? So awful, that Yaz wouldn’t believe such a simple thing?

She’s not sure what to say to prove it, not even sure what to do, but Yaz is still standing there, waiting for an answer, so the Doctor does the first, wordless thing that comes to mind.

She scoops her into a hug.

It’s completely unexpected, she can tell by the way Yaz stiffens instantly in her touch. But then she relaxes, or rather melts, so the Doctor tightens her embrace. To her surprise, despite the overwhelming pain in her head, it’s actually quite nice. Who had guessed Yaz would be so soft?

She lets it stretch on until it grows slightly awkward, then steps back, letting her hands drop to her sides, and then to her coat pockets, because she’s no idea where to put them after that.

Yaz steps back as well, blushing bright red, and fumbles with the hem of her jacket, her eyes glued to the floor. 

“Okay,” she says in a small, embarrassed voice. “I believe you.”

The Doctor stares at her for a moment, a slow grin creeping up her face. She can’t help it; Yaz looks entirely adorable standing there, blushing like a schoolgirl after her first kiss. 

“Course I do, Yaz,” she answers. “And not because you’re one of a kind. Though you are.”

Yaz shrugs, still staring at the floor. She seems fairly abashed for a simple hug, and looking at her, a faint suspicion goes off in the Doctor’s head, but before she can consider it, Yaz speaks, and the Doctor forgets about it entirely. Because the next thing Yaz says absolutely floors her.

“Who says I’m one of a kind?”

And that’s when the penny drops.

“ _Oh,_ ” the Doctor gasps, and spins to face the minute she’s just finished dissecting, astonished. “Oh. Oh, oh, oh, _oh—”_

“Doctor?” Yaz asks, and takes an uncertain step closer. “Did you—did you find something?”

The Doctor is still staring at the minute, chin cupped in her hand, mouth hanging open. For a moment she doesn’t speak, then abruptly she whirls around and grabs Yaz by the lapels of her jacket.

“No, I didn’t!” she jabs a finger toward the minute. “You did, Yaz, you absolute genius! What am I even here for?”

Yaz is flushing again, but the Doctor is too caught up to notice. She spins Yaz to face the minute, and points. “You said it, Yaz, didn’t you? Something familiar, only _I_ thought—oh, but of course it’s backwards!”

“Doctor, I’ve no idea what you’re going on about,” Yaz deadpans, her eyes fixed upon the minute, her brow drawn in bemusement. “What do you mean, something familiar?”

“What you—oh, forget about that. Just something I realized, a while back. That’s the trouble with timelines, see—you never get the events in the right order. So maybe it _is_ familiar, only I didn’t recognize it, because I’ve never seen it, but the other me has! And that means that there _is_ something out there, something like _you,_ Yaz!”

She grips Yaz’s shoulders roughly in excitement, and Yaz nods, though it’s clear she has no idea what she’s going on about. Not that the Doctor minds; as far as she’s concerned, Yaz has just given her the most brilliant idea she’s managed to stumble upon in the past several weeks.

“So…you’re trying to find if there’s anything like me out there?” she asks tentatively, and the Doctor nods, then realizes she can’t see it.

“Got it in one!” she removes her hands and brushes around her, then pauses, and turns back. “Er…I might need another piece of your timeline.”

Yaz looks up from the minute, to the Doctor, then sighs, though she’s grinning slightly under her affected exasperation. A grin of relief, it looks like. Apprehensive hope.

“You’re sure it’s not bad to take minutes from my timeline?” she asks. “I know you’ve said, but…”

The truth is, it’s a small matter to take minutes from Yaz’s timeline because her timeline is such a mess the relative effect is barely worth the worry, but that’s a fairly negative thought, and the Doctor is too euphoric to let it ruin her mood. So she just grins, and claps her hands together.

“Course not! Now, are you ready to get to the bottom of this?”

Yaz smiles, and nods. “Yeah, Doctor. Let’s get to the bottom of this.”

————

It’s a good deal harder to wrangle a piece of Yaz’s timeline into the TARDIS console than it was her grandmother’s watch, but the Doctor does it in the end, and not a moment too soon, for by the time she’s set the TARDIS to scan for similarly broken timelines, the others have noticed as well.

Ryan finds out first, and it happens on what was an otherwise perfectly peaceful day floating in the time vortex. The Doctor has just settled down with a cup of tea, when Ryan comes bursting into the kitchen with wide, terrified eyes, and Yaz hot on his heels.

“Doctor,” he pants, and she lurches to her feet, setting her tea back upon its saucer with a clatter. “Doctor, there’s something wrong with Yaz!”

He points to her, and the Doctor follows his gaze, only to frown, even as her hearts sink, because she has a pretty good guess as to what happened. Only Yaz looks perfectly normal now, wringing her hands anxiously as she glances between her and Ryan with a look of confusion that borders on trepidation.

“Doctor—” she begins, then the Doctor blinks, because Yaz is standing there wearing her police uniform, safety vest and all, her hat tucked under her arm. She gestures towards Ryan, and smiles.

“Guess I scared him, huh?” her eyes have that strange look to them—as if they don’t quite belong to her. The Doctor blinks again, and her throat goes dry. 

“Ryan, there’s nothing to worry about,” she says, and takes a step forward, even though her hearts are thumping. “This is Yaz. She’s just…off, a little.”

Ryan straightens, still panting, and gives Yaz a sideways glance, which she returns with a smile. “Nuhuh. No way. You ain’t Yaz.”

Yaz, frowns, and leans up against the doorway. One hand slides into her pocket, and the other stays tucked around her hat. “Ryan, really? You don’t have to be an arse about it. It’s not _my_ fault I’m here.”

“Isn’t it?” the Doctor’s eyebrows raise, and she takes a step closer, despite the fear trembling in her limbs. She can’t help it; there’s something so utterly wrong about watching a misplaced Yaz talk and move about as if she were occupying her own timeline, when it’s so clear she’s not.

“No.” Yaz tilts her head and broadens her smile, a cheshire cat grin. It’s a strange affectation, a dim echo of her Yaz’s shy grin, only with an added layer of enigmatic knowledge. Of what, the Doctor can’t fathom.

“And I don’t suppose you can’t tell me whose fault it is,” the Doctor says, taking another step forward. Without warning, Yaz’s smile drops, and she shakes her head, as Ryan glances between the two in growing confusion.

“Doctor, do you know what’s going on?”

“Later, Ryan,” she hisses out of the corner of her mouth. One hand slips into her pocket for her sonic screwdriver. She sees Yaz glance down, and knows she knows what she’s about to do.

“I don’t mind if you scan me,” she says, and it’s so close to Yaz’s voice that the Doctor almost thinks she’s come back. But no; the uniform, the safety vest, is still there. Yaz sighs, shoulders dropping. “Not as if my Doctor hasn’t done _that_ enough. Won’t tell you much.”

“Worth a shot.” The Doctor does the scan through the fabric of her coat pocket, before Yaz can change her mind, and in only a moment has the sonic out and held up to her eyes, squinting to get the readings. 

“Any luck?” Yaz asks. She’s got her head at an inquisitive tilt, her shoulder pressed into the doorframe.

“No.” The Doctor frowns, bitter disappointment coursing through her. “But you’re far off from us, aren’t you? And your…oh, your timeline is extremely degraded. Even…oh. I’m sorry, Yaz. I really am.”

Yaz shrugs. Her eyes fall to the linoleum, and stay there. “Expected as much, didn’t I? Not much to be done about it, now. Least, that’s what my Doctor says.”

“Huh.” The Doctor’s brow furrows, as she stuffs the sonic back into her pocket. “Doesn’t sound like me, that.”

“And you don’t sound much like my Doctor,” Yaz says. Her nose wrinkles. “I mean, what is that outfit?”

“Oi!” the Doctor says, and is about to add something even more defensive, only Ryan cuts in before she can get to it.

“Doctor, can you please explain what’s going on?” he sounds scared, almost panicky, and the Doctor winces guiltily, then turns to him, hands held out to reassure.

“Listen, Ryan,” she begins, and gestures to Yaz. “This Yaz—she isn’t _our_ Yaz. She’s—”

“Huh?” 

The Doctor turns to look, and nearly groans, because sure enough, it’s Yaz again. Her uniform is gone, and her body language screams frightened; shoulders shrunk in, hands together, backed up against the doorframe. She looks from the Doctor to Ryan, and opens her mouth as if to explain, or perhaps apologize, then shuts it again.

“Yaz,” the Doctor says in relief, and Ryan too turns to Yaz, then immediately backs away.

“Oh no,” he says, shaking his head. “You’re not—only a second ago you were—”

“What? What’s wrong?” she looks between him and the Doctor helplessly. “Doctor, what happened?”

“Yaz—Ryan—” The Doctor takes another step forward, putting herself within arm’s reach of Ryan. She puts a cautious hand on his shoulder, and he stiffens, then turns around. “Listen, Ryan. I have to tell you something about Yaz.”

“I think you have to tell _me_ something,” Yaz interjects. She crosses her arms, and seems to take comfort in the small act of defiance, enough to push away from the doorframe and straighten to her full height, which, admittedly, isn’t much. “Doctor, what’s going on?”

“You don’t _know?”_ Ryan asks in disbelief. Yaz just looks at him, then bites her lip and shakes her head. 

“But how can you not—”

“Because she doesn’t realize it’s happening.”

Two pairs of eyes turn to face the Doctor. She takes in their blanched, apprehensive faces, and stifles a sigh. This isn’t how she’d wanted to do this. Hadn’t wanted to do this at all, really. But apparently when traveling with three companions, hiding secrets is not the walk in the park she’d been hoping.

“I don’t realize _what’s_ happening?” Yaz asks, the color draining from her face. The Doctor just gives her a weak smile, meant to be encouraging but which she figures is probably not, and gestures to the table.

“Why don’t you two sit down, while I call Graham. I want to explain this properly.”

She explains it over tea that not a single one of them touches. Instead they stare at her throughout the entire explanation, in varying degrees of incredulity, until at the end of it Graham says:

“Now, I didn’t understand a bloody word of that.”

He glances to Ryan as he says it, who shrugs, and replies, “I think I got it, more or less. Not the details, mind you, but the big picture. But what I don’t get is why you’re only telling us now.”

He leans forward as he says this, his eyes on the Doctor, and she finds herself, to her surprise, swallowing nervously. It’s a new thing, being under their scrutinizing gazes, and she’s not sure she likes it. Especially when she has the vague notion that Ryan does, in fact, have a point. 

She should have told them. Should have told Yaz, most of all. 

“I’m sorry,” she says, ostensibly to the three of them, but it’s Yaz she’s looking at. Ryan and Graham stare, she can feel their gazes upon her, but she ignores them, waiting.

Yaz nods, once, slowly. “Okay. But I wish you had told me I’d been—been frightening people.”

_“Frightening.”_ Ryan snorts. “Yaz, you gave me a bloody heart attack, you did. I thought—I don’t even know what I thought. Like one moment you were there, and then you weren’t. It was like—”

“Oi, no need to scare her,” the Doctor interrupts with a pointed look. Ryan falls silent, then shoots Yaz an apologetic look. She gives him a nod, then her gaze falls to the table, and doesn’t rise.

“Alright, so does this mean we have to be on the lookout then?” Graham asks. The Doctor looks to him, confused, and he gestures towards Yaz. “Well, what are we supposed to do about it? Say I go to hand something to Yaz, and it’s a different her? What, am I just going to hand that thing over? She could run off with it, for all I know.”

Yaz snorts in laughter, then quickly goes to stifle it. She shakes her head, then looks to Graham and smiles. “What are you thinking of handing me, a cheese and pickle sarnie? Cos I ain’t touching that.”

“And I ain’t giving it to you neither,” Graham grumbles, but the Doctor sees the sparkle in his eyes, and she’s thankful for it. ‘Course she could trust Graham to bring some much-needed levity to the situation. She really _should_ have told him sooner. 

“No, just—call me, if it happens,” she answers. “I’ll talk to Yaz, figure out if I can learn anything. It’s not permanent, you know. It’s just a result of her timelines mixing up with each other. Her entire timeline is fragmented, and it’s—” Getting worse. “—causing these mixups. Shouldn’t be an issue, while I work out how to fix it.”

“But you _are_ fixing it,” Ryan says. Yaz doesn’t say anything, but her eyes watch the Doctor, anxious. “You’re working on a solution, right?”

“I am.” Her eyes dart between the three, and that age old instinct to throw on a cheery smile, to lie, comes to her lips. It’s her most relied upon trick of the trade. It’s a hell of a lot easier.

But she made a _promise._

“I am,” she repeats. “Nothing’s certain, and I—I don’t know if what I’m doing will work, but I’m doing everything I can. I promise.”

“Okay.” Ryan nods, and leans back in his chair. Graham is looking at her, trust and understanding in his eyes, and Yaz is just watching her, her gaze unreadable. Knowing.

It’s the wrong Yaz, she realizes. The others don’t even notice. 

“I promise,” she says again, and watches the wrong Yaz dip her head, once. Then she tears her gaze away, to the others, and gives a feeble smile.

“Right—speaking of promises. I did say I’d take you to the outer rims of Goire, didn’t I?”

**Notes for the Chapter:**

> questions, comments, 'wtf is happening'....I'll take them all. love to hear your thoughts!


	6. Chapter 6

**Notes for the Chapter:**

> urgh sorry i guys I just woke up so I didn't proofread this one nearly as much as i should have. also, WARNING: this chapter contains a scene of implied lack of consent between another timeline doctor and Yaz. so if that makes you uncomfortable, skip and I'll summarize in an author's note at the bottom. (yeah, i was reading devoted at the time when i wrote it. that story still makes me shudder).
> 
> oh, and as always, thank you for your kind comments! I really love them <3 and I've also gotten several a bit confused about the direction of the story, whether I know where I'm taking it, etc, so I just want to clear things up: I do have a plot and everything! Idk if I mentioned this before, but this story, like every story I post, is completely written out before I post it. I won't post anything I havent already completed, because I don't want to leave you guys hanging. SO don't worry: I promise I know what I'm doing!

“So, what are you working on?”

It’s a lazy drawl, a tone she immediately doesn’t like, and the Doctor cringes unconsciously before glancing up. Sure enough, it’s not her Yaz; rather, this one is wearing dark, ripped jeans and a faded band shirt, combat boots swinging as she perches atop the console. The Doctor’s eyes roam over the placement, and she wants to say something, but bites her tongue and looks down instead. Her Yaz had only been leaning up against the console when she’d last looked—she never would have sat so dangerously close to the controls.

Apparently, this Yaz has no such predilections.

“Nothing,” the Doctor answers curtly, and turns back to the energy pack she’s rewiring. She hears Yaz cluck her tongue, and knows she’s not satisfied. 

“That’s a lame answer.”

“Well, it wasn’t a very good question,” the Doctor says, which isn’t entirely true, but she’s feeling petulant. The energy pack isn’t hooking up properly, and she’s been at it for three hours, and dealt with just as many Yazs. She’s beginning to get sick of all but her own.

Especially when most of them have that _look_ in their eye.

“Oh, c’mon, Doctor,” Yaz says, and when the Doctor can’t resist but look up, it’s right into a salacious smile. “Aren’t you…bored?”

Without thinking, the Doctor reddens and ducks her head down, though she’s not quite sure why. She’s met at least one Yaz harboring a not-so-secret crush, but she hasn’t dealt with any Yaz so…bold. It’s weird. And uncomfortable.

She can feel this Yaz’s gaze upon her, burning into the back of her neck like twin lasers. Quickly, she reaches up and slams her welding mask down, which succeeds only in covering her face, and does nothing to stem the heat on the back of her neck.

Small victory.

The Doctor continues working, hyper-aware of Yaz’s combat boots swinging back and forth, tapping lightly against the underside of the console. She hears a sigh, loud and dramatic, and then another, heavy with something she thinks she understands, but isn’t sure she wants to.

It must be the welding mask, she decides, that’s trapping the heat around her face. She can barely breath for the stuffiness.

After an incredibly long minute, a third sigh comes, then a half-stifled cough. 

“Doctor, you’re being boring,” Yaz whines. “You know, hard to get doesn’t suit you.”

The Doctor nearly drops a heating coil. She nabs it just in time, but succeeds in burning herself, and lets out a curse, muffled behind the mask. 

“What was that?” Yaz asks innocently, and the Doctor hears a thump as her feet hit the ground. A few more light footsteps, then the fabric of her shirt brushes against the Doctor’s shoulder as she kneels down beside her.

“C’mon, Doctor,” she begs, voice low. “I’m bored. And I have a lot of ideas this time around, if you want to—”

The heating coil sparks, and the Doctor yelps, snatching her fingers back, but it’s too late; the tips of her fingers are bright pink, seared.

“Oh, for—” she rears back angrily, and rips her welding mask off, tossing it to the side. Yaz falls back as well, surprised at the outburst.

“Oi, might give me some warning when you jump like that!” she cries, and the Doctor shoots her a glare.

“Might not need a warning if you don’t go around distracting me!” 

Even in a tangled heap on the floor, a slow grin spreads across Yaz’s face. “Distracting you?”

The Doctor doesn’t answer, just huffs angrily, and pushes herself to her feet.

“I need—I need to get something,” she says, and spins on her heel, stalking off towards the hallway. She doesn’t have to look behind to know Yaz is following her; she can hear the sound of her footsteps, the heavy soles of her boots clanging dully against the floor. 

“You don’t need to follow me,” she calls over her shoulder, even as she knows it won’t dissuade her.

“I always follow you when you’re angry,” Yaz calls back, only a few feet behind.

“When I’m—” Abruptly, the Doctor stops and whirls around, planting herself stolidly in the center of the hallway. Yaz, not expecting the sudden halt, nearly crashes right into her, but the Doctor stops her with a steadying hand.

“Oi, fair warning,” Yaz says, and frowns, her eyes running over the Doctor’s face. “Huh. You look different.”

“So do you.” The Doctor frowns herself, and lets her eyes travel over Yaz’s form, scrutinizing. “What do you mean, when I’m angry? When do I get angry?”

Her hand is still clasping Yaz’s shoulder, and Yaz eyes it, then pushes it away. “Really, Doctor? You’re always off in a mood. Half the time you need me to set you right.”

“That—” Immediately, alarm bells go off in the Doctor’s head. She steps back, shaking her head. “That’s not me, Yaz. I’m sorry, I don’t know who your Doctor is, but I’m not her.”

“Oh, I don’t know.” The smile is back on Yaz’s face, and she steps forward, closing the gap the Doctor has widened. “You’re a little off, maybe, but I don’t mind. Why, do you?”

“Um, yes,” the Doctor says, and even though it seems kind of silly, puts her hands up in front of her, as if she’s warding Yaz off—though technically, Yaz hasn’t _done_ anything yet. “Yaz, I’m not—”

“Yes, you are,” Yaz says, and does something entirely cheeky—she puts her hand to the Doctor’s and winds her fingers through, pulling her close. It’s utterly unexpected, and has the Doctor stumbling forward, too surprised to realize what’s happening. “C’mon, Doctor. I know how you get. And I—”

“Yaz, sto—” the Doctor manages to get out, but before she can finish Yaz yanks her close, just a little too rough to be pleasant, and brings her lips to hers, hungry and searching and completely not what she expected. 

For a moment, the Doctor is too shocked to respond in any way. She stands, frozen, until Yaz makes a small noise of impatience and snakes one hand around the Doctor’s neck, forcing her jaw down, and then the Doctor has no choice but to respond.

And the first thing she realizes, to her horror, is that it’s far too easy of a thing to do. Yaz’s lips are soft and inviting, and demanding in a way she hasn’t felt since River, and the entire sensation of kissing in this body is both familiar and new, and sort of wonderful, except it’s wrong, it _has_ to be wrong— 

Only it doesn’t feel wrong. In fact, there’s a moment where the whole thing tips, and then settles into a perfect stillness, the kind that makes the Doctor want to melt into a suddenly gentle embrace, and that’s when she realizes that it’s her Yaz.

Yaz must notice the moment the Doctor does, because she stiffens, then jerks away, her hands coming to cover her mouth. She stumbles backwards, staring at the Doctor in mortification, then abruptly turns away.

The Doctor simply stands there, dazed, and utterly baffled. “Yaz…?”

“Doctor—I—” Yaz still has her back to her, but even from where she stands, the Doctor can see the bright flush creeping up her neck. She stares, perplexed, because of course it makes sense to blush, but Yaz is taking it awfully hard, and she can’t understand why—

Oh.

Realization hits like a well-aimed punch to the gut, and the Doctor feels like an idiot.

“Yaz, hang on—” she starts to say, and doesn't finish, because her next words are drowned out by the sudden blare of an alarm. Only it’s not the regular alarm. It's not an alarm she recognizes at all, which means it must be new. And the only new alarm she can think that she's installed is—

“The scanner!” she gasps. “Yaz, that's the alarm for the scanner!”

Yaz’s head jolts up, then she turns around. “It is?”

“Yes, of course!” The Doctor bobs her head, relief and excitement coursing through her, because finally, _finally—_

“C’mon!” She grabs Yaz’s hand and takes off, back to the console room. Yaz stumbles, then rights herself and follows, half dragged by the Doctor’s enthusiasm. 

When they reach the console room, Graham and Ryan are already there, both in pajamas, looking confused and more than a little worried.

“This better not be an emergency,” Graham says crossly. “We've only got about five hours and I told you I need at least seven if we're going to do proper life saving stuff.”

“Not at all,” the Doctor answers, and lets go of Yaz’s hand to practically skip to the console. She can't help it; the buoyancy of possible success, after weeks and weeks of nothing, propels her easily into the exact sort of mood she's been faking.

Though of course, it could also be nothing. She'd just rather not think about that.

“So what is it?” Ryan asks, stifling a yawn halfway through. Clearly the threat of a possible emergency hasn't spiked much adrenaline in him. Possibly, the Doctor thinks, they're just getting used to the call.

“It's Yaz.” The Doctor bends over the console and squints at the monitor which bears the readings. “I've set it to scan the time-space continuum for similar readings—”

“The time-space continuum?” Graham interrupts. “The entire thing?”

“ _Yes,_ Graham,” the Doctor answers, still squinting. “I've got to cover my bases, don't I? Better to do the whole thing, you ask me. Anyway, as I've said, I've set it to scan for similar readings, see if there's anybody else out there like our Yaz. And it looks like—”

She straightens up, and shoots them all an enormous, triumphant grin. Her eyes fall lastly to Yaz, and linger. “—Like you're not the only one, after all.”

In that moment, the relief on Yaz’s face is worth a thousand headaches. 

“So you can cure me?” Yaz asks. The Doctor’s enthusiasm falters at the words, only for a moment, and Yaz backtracks. “I mean, you can find out what’s wrong, at least?”

“You can?” 

Both Ryan and Graham are looking at her as well, their faces drawn up in confused hope. The Doctor looks to them, then back to Yaz, and realizes sometime in the middle that she’s clasping her hands together nervously. She hesitates, then sucks in a deep breath, and says:

“Yes. Yes I can.”

Now there’s nothing for her to do but prove it.

————

The signal leads them fifteen thousand years into the future, to a desolate asteroid that would probably be devoid of all life, if it weren’t for the temporary research facility perched atop the surface. 

“Research facility?” Graham asks the Doctor as she circles around the console, grabbing some last minute tools; a few screws, a piece of string, a battery, a couple of custard creams. Useful things. “How do you know it’s not some army base, and they’re going to blow us to bits the minute we walk out that door?”

“Optimism, Graham!” the Doctor reprimands, and scowls as she steps down on the custard cream dispenser, and fails to receive a biscuit for the tenth time. She looks up to the central pillar of the console, and scowls.

“I’ve only had three,” she grumbles, but removes her foot anyway, and turns to face the others.

“Of course it’s a research facility!” she answers to their dubious expressions. “If it were a base, there would be patrols, guards, big old energy signals—and a lot of them. But here, besides all the general life-preserving equipment, I’ve only picked up one.”

“One energy signal?” Ryan asks. 

“One _big_ energy signal,” she corrects him, and smiles the kind of smile she hasn’t had cause to wear in a long time; the kind that comes with plunging into a mystery.

The Doctor does love a good mystery.

“So you think it’s some type of experiment, don’t you?” Yaz asks. The Doctor glances at her, and her smile drops for a split second, before she forces it back up again. Yaz is wearing a footy uniform again, this time dirtied and grass-stained, the plait in her hair messy and loose. She looks as if she’s just come off the field.

“Yeah, suppose it is,” she answers, and tries not to cringe as Ryan and Graham glance uneasily toward Yaz, but don’t say anything. They’ve grown accustomed, if not used to, Yaz’s sudden changes. Or, at the very least, they’re polite enough not to point them out.

“So, gang—fam?” she grins, and claps her hands together one last time. “What do you say we go check it out?”

One by one, they glance to each other, then nod. Even Yaz.

The Doctor extends the air corridor right up to the front door, which she supposes is a little presumptuous. But then, it’s not as if they’ve posted guards. In fact, the entire facility itself doesn’t look very well protected, and it’s enough to make the Doctor wonder if the place is, in fact, abandoned, until the door swings open, beckoning them straight into an airlock.

“Right, that was easy.” She glances over the doorway, looking for some kind of laser barrier, but finds nothing. Odd. But then, it’s the fifty-second century, which places laser barriers fairly on the old-school side of the spectrum.

“Doctor, are you sure this is safe?” Yaz asks. “This all seems…too easy.”

“Um…” The Doctor glances to her, and suppresses a sigh of relief when she realizes it’s her Yaz. “To be honest Yaz, I’m not sure. But I’d say it’s worth checking out, yeah?”

“Not worth checking out if we’re dead,” Graham grumbles, but when she raises an eyebrow at him, he just purses his lips and gestures for her to go ahead. 

“I’m with Grandad,” Ryan says, and at the Doctor’s swift glance, shrugs. “And Yaz. Too easy, isn’t it?”

The Doctor frowns, and presses her lips together in something close to a pout. “Oi, don’t be spoilsports. Best way to find out is to try, right?”

“And die,” Graham chimes in, and at the Doctor’s glare, gives an exasperated sigh. “Al _right_ Doc, I trust you. But if we all asphyxiate or something…”

“You lot are the most pessimistic I’ve ever seen,” the Doctor grumbles, and makes a point to step inside the airlock, raising her eyebrows in challenge as she does so. “C’mon, who else?”

“Alright, we’re coming,” Yaz answers, and steps inside, if not a tad reluctantly. She turns to the others as well, and makes a show of crossing her arms. “You two coming?”

The boys look to each other, then slowly shuffle inside as well, jumping as the doors slam shut behind them.

“Yeah, because that’s not ominous,” Ryan says. “We’re going to get murdered, aren’t we?”

“Pessimistic,” the Doctor mutters, and turns to the second door. She plants herself in front of it and frowns, rocking back on her heels. “Hmm. This should be open by now. I wonder why—”

She cuts off as a _shiick_ echoes throughout the chamber, followed by a pneumatic hiss. “Huh. Okay. That doesn’t sound good.”

“Yeah, that definitely doesn’t,” Yaz says. She looks around, then up to the ceiling. Her eyes widen, and she points. “Look!”

They follow her gaze, and draw in three sharp breaths. A coiling gray gas billows from the ceiling, streaming from each corner in continuous waves before sinking slowly down to where they stand.

The Doctor raises her sonic and scans quickly, before bringing it down to have a look. As soon as she sees the reading, she lets out a quiet curse.

“Deadly,” she says, and shakes her head in frustration. “Oh, I am an idiot. Of course, those that work here probably have a special code that allows them to—”

“Uh, less talking, more doing?” Ryan suggests in a high, frightened voice. The gas is sinking down to their level, filling the room with noxious fumes and what feels like oily, gray smoke.

“Right! Sorry!” The Doctor spins around, scanning the walls for something—there! She dashes to the left hand side and presses a panel, which pops open to reveal a keyboard, a hand print, and what looks like a voice receiver.

“Ooh, the sonic doesn’t do hands,” she moans, then aims the screwdriver at the voice receiver. It crackles momentarily, then beeps.

Immediately, the Doctor leans down, and begins to speak. “Hello? Hello, is anybody listening?”

She pauses, breath held, vaguely aware of her friends cowering behind her. For several seconds, there’s silence. And then—

“Yes? Who is this?”

She almost drops to the floor in relief, but instead collects herself and begins to speak. 

“Hello, my name is the Doctor, I’m here with my friends. We’ve come to inspect your facility, it’s a surprise visit, and I have the papers to prove it. We weren’t aware, however, of your—uh—”

“Precautions?” the voice crackles over the line, tinny and rather annoyed. “Who are you that you don’t know—”

“We’d rather explain later, if that’s alright with you!” she can feel the gas settling on the back of her neck, soaking into her clothes, and moments later a burn begins to spread across her shoulders—

“Alright, alright,” the voice sighs, and the Doctor hears a series of key-clacks. She stays frozen, barely breathing, and hardly daring to look up, until she’s certain—

“It’s disappearing!” Yaz cries behind her, and the Doctor lets out an enormous breath. She sags for a moment, before straightening up, and turning around to meet her friends’ faces.

“Right,” she says, and tries not to wince under their combined glares. “So, that was a bit of an adventure, wasn’t it?”

**Notes for the Chapter:**

> summary for those who skipped: angsty alternate timeline yaz bugs the doctor, follows her and kisses her without asking, then turns back into regular yaz, which causes the doctor to realize yaz has a crush on her. Just then the alarm indicating they've found an energy reading similar to Yaz's goes off, and they follow it to a research facility in the 52nd century, on an empty asteroid. they go up to the front door, so to speak, and get let in, only to nearly narrwoly be killed by a poison gas in the airlock designed to weed out intruders. Why? drama.


	7. Chapter 7

**Notes for the Chapter:**

> oh hey guys, so every third day I post an update. Sorry if it's confusing, let's just call it timey wimey. Also, as always I absolutely loved your comments and theories! I can neither confirm nor deny any of them, unfortunately. And to those who are impatient about finding out, I promise that is coming soon. I mean, we're on the 7th chapter, and there's only 11. We're getting there, I promise.

The second door swishes open not a minute later, and they step out into a drably-lit hallway, off-white lights glinting against dingy, gray-paneled walls and a scratched floor. The place looks old, worn; as if it’s been built on a shoestring budget and maintained as such ever since.

“Some research facility,” Ryan comments, and even as the Doctor waves her hand to shush him, she can’t help but agree. It’s eerily quiet; only the soft _scuff-scuff_ of their shoes echoes in the dead empty silence.

“Where did that bloke say to go?” Graham asks, and the Doctor opens her mouth to answer, only to realize that she doesn’t, in fact, know.

“Er…continue down the hallway, I imagine, and we’ll meet him…somewhere.” She tries for more confidence than she’s feeling, but a quick glance off to the right tells her that Graham isn’t buying it. Neither is Ryan, for that matter.

But a moment later Yaz comes up quietly beside her and, without announcement, slips her hand into hers. The Doctor looks at it in surprise, then to Yaz, and opens her mouth to say something, but before she can realize the error of that idea, Yaz leans in and whispers:

“Doctor, I don’t feel good. Here. This place is…it’s making me see double.”

“See double?” the Doctor looks at her in confusion. “What do you mean?”

Yaz shrugs uncomfortably, and eyes the gray paneled walls. “I…I don’t know. It’s like, those _things_ you did, yeah? Only it’s all at the same time, and nothing ever changes. But it’s happening at once, and I—ow—”

She cuts off and blinks fiercely, then draws her hand out of the Doctor’s to rub her forehead. When she brings it down again, she doesn’t retake the Doctor’s hand, but stays close and leans in.

“But you get what I’m saying, yeah? You said you see things…differently than us.”

“I—yeah.” The Doctor blinks and makes an effort to keep looking at Yaz, even though it’s getting rather hard. She’s incredibly hazy, and the Doctor hasn’t bothered to take any headache pills, which is starting to look like an obvious oversight. She blinks again and Yaz is on the other side of the hallway, walking next to Graham. Another blink, and she’s back beside the Doctor, their hands once more entwined.

She’s not sure Yaz notices, but she doesn’t let go of her hand. Instead she leans in and says, in the most self-assured voice she can muster, “I know what you’re talking about, Yaz. I think this means we’re getting close. To whatever it is that’s causing this. We got this, you know? We’re gonna figure things out.”

Yaz gives her a small half-smile, and tightens her grip. She doesn’t seem to notice that they weren’t holding hands, or if she does, she doesn’t say anything. 

“Thanks Doctor. I trust you.”

“T-thanks.” It’s a heavy weight to drop on her, those words, particularly here and now. She’s heard them before, from Yaz herself, but now that they’re closing in on whatever this mystery is—and she can taste how close they are—it seems suddenly overwhelming. And the Doctor isn’t good with personal pressure. She has a habit of running away.

_A promise._ She mouths the words, and wills herself to believe them. Can’t run away now, whether she wants to or not. Or rather, she just won’t.

They continue down the dim hallway, and the Doctor is so preoccupied with those words sitting upon her that it comes as a surprise when she rounds the corner and walks right into a man.

“Hey!” he says, and takes a step backward, hands held up in front of him. “W-who are you? You’re not supposed to be here!”

The waver in the man’s voice that sets off the Doctor’s suspicions. She’s not sure for what, but since the man is still looking at them all like he’s about to sound an alarm, she pushes that to the side and steps forward to deal with the problem at hand; namely, their cover.

“Actually, we are supposed to be here,” she says, as one hand reaches surreptitiously into what she hopes is the right pocket for her psychic paper. Would be pretty embarrassing if she repeated the same mistake twice. “We’re inspectors, come to look over the facility. Unannounced, of course. Though you could have warned us about the airlock, thanks.”

“Warned you—” the man’s mouth works uselessly, and he squints over the rims of his glasses, as if trying to recognize them. “Hang on. Are you from—”

Before he can finish that sentence, she seizes her psychic paper and draws it out, thrusting it into his face. He peers at it, and she watches as his mouth drops open, eyes growing round with shock, then horror. 

“Oh—you are! But I thought—oh, but—we’re not ready,” he finishes lamely, and glances between them, apprehension clear on his face. Then he lets out a huff of a sigh, and runs his hand through curly brown locks before sticking both into the pockets of his lab coat. He stares at them for a moment, then lets out another sigh, shoulders drooping.

“Yes, I suppose we’ll have to do the tour then, won’t we?”

“Yes—tour! That’s great, we’ve been dying to see the tour.” The Doctor glances between Ryan, Graham, and Yaz, who all nod quickly, with varying degrees of conviction.

“Yeah, I love tours,” Yaz volunteers, and Graham bobs his head up and down in agreement.

“Me too, can’t get enough of them.”

“And me,” Ryan adds. “Might want to run us by the basics though, just to make sure we’re on the same page.”

“That is a _brilliant_ idea.” The Doctor shoots Ryan a proud look, and he grins, before quickly stifling it. The Doctor turns back to the man, watching them with a baffled expression, and raises an eyebrow. “Right, as my—associate, said, we want to start at the bottom, work our way up. And the best way to do that is with introductions, yeah?”

“Right.” The man nods, mouth still hanging slightly agape, as if he can’t believe he’s doing this, _right_ now. Abruptly, he gives himself a shake and snaps it shut, then extends a hand, which the Doctor meets readily. “Right. Well, my name is Arnold Turner, and it’s actually rather lucky you met me, I suppose—” his face twists on the word lucky— “because I’m the head scientist here at TIAR.”

He pronounces it ‘tire’, and the Doctor frowns, but before she can ask, Yaz beats her to it. “What’s that stand for, tire?”

He smiles, as if he expected the question. “Suppose they didn’t brief you much at the agency, then? I understand, we’re a bit of an offshoot. They don’t like to talk about us much, do they?”

_Agency._ The word sings a warning bell in the Doctor’s brain. She shakes her head. “No, sorry. They just told us we’re inspecting a facility. So, care to fill us in?”

“Course, course.” He nods, and smiles wearily. “It’s T-I-A-R. Temporal Investigation and Research. Not very imaginative, as you can see.”

“Well, it gets the job done,” the Doctor answers absently, her mind reeling. She glances to Yaz, and sees her own thoughts mirrored; _we’re on the right track._

She almost hopes they aren’t. Because the more she listens to the man, the more the Doctor gets the sense that there’s something terribly off about the entire situation.

But then, there’s been something terribly off since she fell through the roof of that train, hasn’t there? And if there’s anybody who can put it right—

“Ah, I didn’t introduce myself, did I?” she smiles, and bounces on the soles of her feet, then sweeps her hand across the four of them. “I’m the Doctor, and these are my associates—Ryan, Graham and…Yaz?”

She stops short, her throat suddenly filling with trepidation. Yaz is bent over double, arms wrapped across her chest, and as the Doctor watches, she drops suddenly, as if she’s about to collapse. Ryan rushes forward to catch her, but before he can make it she stands up straight, and turns with a smile. 

“I’m fine,” she says in a serene voice, then turns to the Doctor and Arnold, and gives him a smile. Her eyes, the Doctor notices, are someone else’s. “Sorry, had a bit of a turn. Not good with travel.”

“Oh. It’s completely understandable.” Arnold blinks, then offers a polite, nervous smile. “It’s a bit of a hike.”

The Doctor watches him as he speaks, eying his reaction, gauging. Only it’s rather…normal. Nothing strange, nothing knowing. He seems nervous, but not unusually so.

Curioser and curioser.

“So, about this tour?” she prompts him, and he turns to her. 

“Right, right. And I suppose you have—” for an answer, she flashes the psychic paper, and he glances at it, then sighs. “Yes. Full clearance. Alright. Let me show you what we do.”

He turns, and without looking back, calls, “Follow me, and please don’t touch anything!” Then he’s off, moving down the hallway with his lab coat flapping behind him. The Doctor glances to Yaz, who isn’t Yaz, then to the other two, and tilts her head.

“Let’s get a shift on?” She phrases it as a question, but doesn’t let them answer, before taking off after Arnold herself, leaving the three to follow in her footsteps.

And they do.

————

“Right, I suppose you’re not interested in the living quarters or any of that nonsense? Not that kind of inspector?”

The Doctor jerks from her reverie, examining the multitude of doors they’re passing by, then meets his questioning gaze and shakes her head. “Got it in one. We’re really just interested in the, er…project.”

As far as word choice goes, it seems a good guess; by the way Arnold purses his lips together, she can tell that he’d rather they tour the barracks, or whatever it is they’re sleeping in.

“Yes, so I thought,” he says rather sourly, and pulls up short in front of a door, as innocuous as any of the others. “Well then, I suppose we'll start at the hub.”

“Hub?” Yaz repeats, and the Doctor glances to her. It’s the right Yaz again, a small, inquisitive frown on her lips. “Hub for what?”

“Communications hub, sort of. It’s a bit hard to describe, but—well, you’ll see in a second.” Arnold shrugs, and without looking, presses a hand to a square on the wall. Lights flash up around his handprint, and moments later, the door slides open, revealing a circular room lined with rather ordinary looking desks, across which a handful of people are scattered. None of them are wearing lab coats, but all look busy, talking into what the Doctor guesses must be nano-hearing implants, as holographic displays cast series of numbers and images, too fast to catch a glimpse.

“Bit underwhelming,” Graham mutters as they step through the door, only to be silenced by a jostle in the ribs from Ryan.

“It looks as if you’re understaffed,” the Doctor observes, as the handful of heads swivel to glimpse their entrance. “Funding troubles?”

“You could say that.” Arnold gives her a funny knowing grin, as if the Doctor is in on a joke she knows nothing about. She nods, and decides to return it. “Fewer people, fewer mouths, fewer loose lips. There’s an old earth saying about it, I think.”

“Don’t think I’ve heard it.” The Doctor glances around, and catches the eye of a young fellow with tousled orange hair, who gives her a wave and a grin. “And what does this lot do? Excuse my ignorance, we’ve really been kept in the dark.”

“Ain’t that the truth,” the tousle-haired fellow says. “Are you the ones who got stuck in the airlock?”

“Sounds familiar.” The Doctor gives him a nod. “Are you the one who got us out?”

“Yep.” His grin grows brighter. “I saved your lives.”

“Oi, after trying to kill us in the first place!” Yaz brushes past the Doctor, glaring at him. “That was a pretty nasty trick, you know—”

“The airlock is automatic,” Arnold interrupts, and casts a ‘help me’ glance to the Doctor, who quickly puts a hand across Yaz’s chest, stopping her from advancing further. “It activates if you enter without the proper protocols. My apologies, sincerely. We weren’t expecting visitors. Especially not from the Time Agency.”

“The—” the Doctor spins to face him, the blood draining from her face. “What did you say?”

“Uh—” Arnold balks at her reaction, then immediately turns suspicious. “Aren’t you—”

She’s given them away, the Doctor realizes. Quickly, even though she knows it’s improper, not to mention dangerous in their current situation, she pinches the timeline they’ve entered, the one where they get found out, and drops it off to the side, making room for her preferred timeline to fill in the gap. Then she sets back, and waits for Arnold to mention the Time Agency.

“….especially not for the Time…Agency…”

He trails off, gaping. She frowns, puzzled, and as the moment stretches on, glances helplessly around the room, at the employees who look just as baffled as she does. As Ryan, Yaz, and Graham do. 

“Uh, Arnold, sir?” the tousled-haired fellow asks. “Is everything alright?”

At his words, Arnold blinks, then seems to jerk back to reality. “Um—yes! I’m—I just didn’t realize they sent…” he trails off again, only this time is face is filling with a strange excitement. “Well, I guess we’ll forget the rest of the tour then, won’t we?”

“But we were just gettin—” Ryan starts to say, only this time it’s he who gets interrupted by a swift nudge, coming from the Doctor.

“Why do you want to skip the rest of the tour?” she asks suspiciously, but Arnold just bounces on the soles of his feet, hands clasped together. He looks positively elated now, glancing between the four of them as though they’ve provided the answer to his prayers.

“Not skip, exactly, but just—well I’ve got to brief you, don’t I? I didn’t realize it was _that_ kind of—” he shakes his head, once, then glances to the workers at the desks, who are staring at him with equal confusion. “Never mind. Let me get you to the control room, and then we can talk.”

He half-turns, and gestures to a door on the far side of the room, as plainly painted as the rest of them. She’s beginning to think it’s a theme. “Shall we?”

She hesitates, then nods, and steps forward. “Didn’t really want to see the boring bits anyway, if I’m being honest.”

“Yep, us neither,” Graham says, and steps up as well, only for Arnold’s eager smile to falter. 

“Sorry, but…” he beckons towards the Doctor. “Only her. She’s the only one with the right kind of…clearance.”

His voice lays oddly on the last word, making it very obvious that he’s not talking about clearance at all. But the Doctor frowns, and crosses her arms. “Sorry, but these are my associates. I bring them everywhere with me.”

Arnold just shakes his head. “I really am sorry. But I can’t show them what I have to show you. I shouldn’t even be—” he glances towards the workers, watching him with interest, then back to the Doctor. His voice drops to a strained whisper. “—like I said. Shall we?”

The Doctor pauses, stymied. She wants to take a glimpse at the timelines, see if there isn’t one where she can’t convince him, but now that she knows he can see, she has the awful naked feeling of being watched. So she doesn’t. Instead she looks back to the others, watching her expectantly, and her gaze falls to Yaz.

It’s her Yaz. And when the Doctor meets her gaze, she gives a smile that’s too weak to be a smile at all, only a nervous twitch of the lips. Then she drops her gaze to the floor and curls her hands into tight, white-knuckled fists.

“Right.” The Doctor turns back to Arnold, and gives a bright, slightly dangerous smile. “Just me. And Yaz, here." She gestures to Yaz, whose head jolts up in surprised hope. “She has to come with me.”

“But—” Arnold begins, but falls silent at the Doctor’s tiny, warning shake of her head.

“She’s a part of this too,” she says, soft enough so as to be heard just between the three of them. She can feel on her back Yaz’s grateful gaze, but doesn’t give in to it just yet. Instead she watches Arnold with one raised eyebrow, waiting.

After a long second, he gives in and sighs. “Alright. If you insist. But if you’re wrong about any of that, we may have to kill her.”

He says it matter-of-factly, and the Doctor only nods, even as she hears twin sharp intakes of breath from behind her. She wonders who they belong to. “Of course. I wouldn’t expect anything less.”

“Thanks, Doctor,” comes a low hiss off to her right, but she ignores it, because Arthur is straightening up and fixing his smile back upon his face. It’s slightly weaker than before.

“Okay, then. The two of you.” He gestures once more to the plain door. “We’ll have to hurry before the next shift goes out, but I think we’ll manage it.”

The Doctor nods, filing this away for later. “And my other associates?”

“Ah—yes.” Arnold rubs his chin, and casts his eyes around the room. They alight upon the tousled-haired bloke, sitting a few meters away, whose face immediately drops. “Rezik, can you show them around? Give them the regular tour.”

Rezik’s face comes dangerously close to a scowl, and he grumbles as he scrapes his chair back, rising to his feet. The Doctor looks back and sees Graham and Ryan exchange a look. 

“I’ll be back,” she whispers. “ _We’ll_ be back.”

Ryan shrugs, as does Graham, neither looking too happy about the situation. But they say nothing, and when the Doctor turns back to Arnold, it’s to find he’s already started across the room, clearly impatient about the briefing.

Yaz is standing beside her, looking uncertain as she fiddles with her jacket hem, so the Doctor gives her a jostle and, when she looks up, a smile. 

“Brave heart, yeah?”

Yaz looks to her, and after a beat, returns it.

“Yeah.”

**Notes for the Chapter:**

> So this one's a bit slow, but again the mystery deepens. I hope you guys are enjoying, I really do. And as always, I absolutely love hearing your comments, even if I can't get back to them. I appreciate every single one.


	8. Chapter 8

**Notes for the Chapter:**

> okay so I was going to post this on tuesday but my friend Jolivira had a bad day so this one's for you!! though you may hate me by the end of it, oops.

The door is opened by a handprint, and leads to another short hallway, this one lined with large windows. Behind each window is a room, all crowded with what the Doctor recognizes as computer servers, their soft hum audible even through the glass panes. At the end of the hallway is another plain door, but Arnold veers off right before they reach it into one of the windowed rooms. This one, in contrast to the others, is empty except for a bulky, circular console stood in the middle of the room, rimmed with buttons and as equally gray as the walls. She’s starting to wonder if they couldn’t invest in another shade of paint.

The moment they all crowd into the room, Arnold turns around and clasps his hands together, grinning.

“So you’re it then? You’re the specialist we requested?” he asks. His eyes are laser-focused on the Doctor. 

“Specialist?” the Doctor asks. Her eyes dart to Yaz, who simply gives a minute shake of her head, uncomprehending. “Specialist for what, exactly?”

“For the project,” Arnold says. He’s grinning madly, as if he’s just been given the best news of the week. “I assume the inspection was a cover, only I didn’t realize until you did that thing in the hub—”

“Right. Thing. You weren’t supposed to see that, actually.” the Doctor frowns, eyes glinting, and steps forward, peering into his face. “How were you able to see that?”

Surprised, Arnold takes a step back. He looks to Yaz, then to the Doctor, and says, “I, uh, didn’t see exactly what you did. But it set off this.” he turns, and pushes back curly hair to reveal a silver dot, pulsing with green light, nestled behind his ear. He lets them take a look, then moves his hand away and turns back around.

“It senses temporal distortion. Well, temporal manipulation. It was one of the first things we designed when we began working here, obviously. With the risky work we’re doing out in the field, we need to know when something is going wrong.”

“Oh— _oh.”_ The Doctor’s eyes widen, and distantly, she wonders if it’s possible to be so lucky so many times in a day. It’s almost too easy, the whole operation. But she’s not ready to question it, not when they might be so close. “So it sensed the temporal manipulation, is that it? I’ll say, that’s a genius piece of equipment right there. Way ahead of the fifty-second century.”

“Er, thanks.” Arnold eyes her uneasily. “So, I take it you’re the specialist we requested? Suppose you didn’t want to mention it in front of the hub workers. Their clearance isn’t all that high.”

Out of the corner of her eye, the Doctor catches Yaz’s gaze, watching her. Waiting for her to do something. Quickly, she nods, and smiles. “Yep! You’re spot on, actually. That’s me. Uh, me and my assistant.”

She gestures to Yaz, who looks none too happy at the label, but doesn’t protest. Arnold gives her a perfunctory nod, then turns once more to the Doctor. 

“So, Doctor, how much do you know, really?”

“Uh—” she shakes her head, affects an abashed expression. “Nothing, actually. So top secret they won’t even let us in on it, apparently.”

Arnold snorts. “Well, that’s more or less accurate. Right, I suppose I’ll start from the beginning.”

He turns to the console in the center of the room and begins punching buttons. A hologram flickers to life, forming into a 3-D replica of what looks like an empty stretch of the asteroid; rocky ground, empty space around it. The Doctor frowns, and steps closer, Yaz trailing behind.

“Is that here?” she asks, nose scrunching as she bends down to get a closer look. “On the asteroid?”

“Yes, of course,” Arnold replies, still punching in commands. The scene rotates towards them. “This is actually only a few hundred feet from our lab. Less, even. It’s the reason we’re here.”

“ _That’s_ the reason?” Yaz steps closer, frowning as well. “It doesn’t even look like there’s anything there.”

The Doctor leans in, squinting, and thinks, _Yaz is right._ It doesn’t look like there’s anything there.

“Yeah, sorry.” She straightens up, and turns to Arnold. “I think we’re going to need a bit more of an explanation. What are we meant to be looking at? And how do you expect us to help?”

“Hmmph. They really have kept you in the dark, haven’t they?” Arnold brings a hand to his chin and rubs, thoughtfully. Then he chuckles, bitterly. “’Fraid I can’t be surprised. It _is_ the Time Agency. They do like their cloak and dagger, don’t they?”

“They sure do,” the Doctor nods knowingly. “But, aren’t you, er, part of the—?”

“Oh, definitely not!” Arnold shakes his head, disgust creeping across his face. “No, we’re private contractors. Best in the galaxy, actually. But we work closely with the government, and as you know, that means the Time Agency. Quite a lot these days, as well.”

“You don’t seem to like the—us,” Yaz pipes up. “Why is that?”

Arnold looks at her, surprise and then dismay flashing across his expression. “Oh, no! I—well actually, you know what? It’s a free galaxy, isn’t it? I suppose you lot won’t throw me out of my facility if I say I don’t fancy all the work the Time Agency does.”

Together, Yaz and the Doctor shake their heads. 

“No, that’s fair,” the Doctor says. “But then, why work for them at all? You seem like a good scientist, Arnold. Why not find work elsewhere, if you’ve got a whole galaxy to search through?”

Arnold sniffs. “Maybe in another line of work. But no, for a temporal engineer, the best projects are with the Time Agency. Unfortunately. I mean, there are a few other research sites, but the Time Agency has the most money, which means they’ve got the most funding. And perhaps I’m an ambitious old fool, but I want to be on the cutting edge. There’s so much to explore…”

He trails off, shaking his head. “Anyway, I’m distracting us from the briefing. And we really do need to get a move on, if you want to make the next shift, so—”

He brandishes a hand once more towards the display. “Right, so. That’s actually a good place to start. The cutting edge. Now, what did you say you both saw here?”

“Nothing,” Yaz volunteers before the Doctor can, for which she is silently thankful. She can guess what kind of lecture Arnold is about to go into, and she hates being on the receiving end of things she already knows. No matter how necessary.

“Right. Well, wrong.” Arnold rubs his hands together and grins, an excited glint in his eye. “Yes, it does appear as if there’s nothing, that’s true. But that can be true only in this universe. See, if you know anything about multiverse theory—”

“Yes, we studied it,” the Doctor interrupts. Arnold’s face falls, and she only feels a little bad. She can only take so much lecturing. “In the Time Agency. Did a course in preparation, though we didn’t know why. Now I supposed that’s all cleared up, yeah?”

“Yes, I suppose.” Arnold looks distinctly less enthused. Yaz also looks slightly disappointed. “Okay then, since you’re all caught up—”

He turns and begins zooming in on the same innocuous point, explaining as he goes. “What we’re doing here is examining time as it relates to other universes. Parallel timelines, that kind of thing. You see, the more we learn, it’s almost as if the less we understand, but we’re starting to catch on to a few things. For instance, why timelines don’t intersect with each other—”

_Generally,_ the Doctor thinks, but doesn’t say anything. Arnold is still zooming in on the hologram, smaller and smaller. “So, you’re examining timelines, then?”

Yaz is leaning forward eagerly, hopeful interest writ across her face, but Arnold shakes his head, still looking at the hologram. Yaz’s face falls.

“No, actually, though our interest does lead from there. You see, when we started studying timelines, we began to wonder if we could access them. View them, from our own universe. So we began looking.”

It all sounds like the sort of human meddling the Doctor would have to jump in to sort out for them, but she refrains from criticizing, though she desperately wants to. “Something tells me you didn’t find timelines though.”

Mainly because if they did, the universe would be a whole lot more ripped apart than it currently is now, Yaz notwithstanding. But she doesn’t say that, either, just waits as Arnold considers her question. He’s still zooming in on the hologram, though at this point she can’t tell for what.

“No, we didn’t. We found something a lot more interesting. And I’m almost—here we go!”

He nods his chin towards the hologram and they both look. For a moment, there’s nothing, though he’s still zooming in, and then, after a beat, something small appears. A dot, nearly indistinct. Arnold keeps on expanding it, and it grows, and grows, until, when he finally lowers his hands and steps back, it’s the size of a baseball, a roiling golden orb of light that floats freely over the console. Arnold grins proudly, and gestures towards it.

“ _This_ is the real thing we’ve been looking for. You see, when we began searching for timelines, we didn’t find them, but we found other things.”

“Like this?” Yaz asks, bending forward and squinting to examine the golden orb. Arnold bobs his head.

“Yes, exactly! This, and many others, scattered throughout the universe. Testing shows us they’re heavy with artron energy, only we don’t know _what_ they are. All we know is that they don’t seem to do anything, and that they have to do with time.”

“What do you mean, they don’t do anything?” the Doctor asks. She steps forward and leans down with Yaz to scrutinize the orb. There’s something about it that tickles her memory, though she doesn’t know why. An idea, that floats just beyond her grasp. She can’t help but feel that she should know what this means.

Only she’s no idea.

“I mean, they don’t affect the space-time continuum,” Arnold answers. He’s got his hands still clasped together, churning with eagerness as he watches them examine the orb. “They exist, we’ve made sure to check that, but they have no effect on our universe. It’s like they’re here, and not here. And we’ve no idea why.”

_Here, and not here._ A chill runs down the Doctor’s spine. Abruptly she stands up, and looks to Arnold. “So, I suppose that’s what you’re trying to find out? What they are?”

“Exactly!” Arnold exclaims. Then his face falls. “Only, as you can tell, we’re more than a little lost. We’ve been hacking away at the thing for months, trying to get some inkling of what it does, or why it exists. But we’ve made almost no progress.”

“Almost?” the Doctor prompts. Arnold nods.

“Yes, almost. The only thing we’ve managed to figure out beyond registering the high levels of artron energy—which is really quite basic—is this.”

He twists his hands over the hologram again, and the display changes, red numbers and diagrams flashing around the orb. The Doctor leans forward to properly read them.

“Those pressure readings are off the scale,” she observes, eyebrows high in surprise. “Almost as if—”

“As if it’s taking a massive amount of pressure from something we can’t see,” Arnold confirms. “And of course, we’ve no idea what. That’s where you might be able to help us out. Actually, you’ve arrived at exactly the right time, because we’re about to send out another shift.”

The Doctor straightens up immediately. “Shift. You keep saying that. What do you lot actually do on these shifts?”

Arnold snorts. “Realistically? Nothing substantial. Optimistically? Test the object. Try to interact with it, in some way. Today we’re going to try to access it again, hopefully take a sample. After you look at it, of course. Er, you are going to look at it, aren’t you?”

The Doctor opens her mouth to reply, but to her surprise, Yaz beats her to it. “Course we are. That’s what we’re here for, aren’t we?”

“That we are,” the Doctor repeats, and throws a small frown to Yaz. She receives a tiny shrug in response. “Right, as my assistant said, we’d be happy to take a look at it.”

Now she can just _feel_ Yaz’s disgruntled look burning into the back of her coat, but she chooses to ignore it. Arnold looks between them, puzzled. “Both of you are planning to come? I don’t think—”

“She’s my assistant,” the Doctor answers firmly, and hears a small huff from Yaz’s direction. “Of course she comes.” 

“Right.” Arnold still looks uncertain, but after he doesn’t push the subject. “Okay, then. Well, let me just take you to the briefing room, Anta and Regis should be getting ready just about now. They’re the scientists who’ll be accompanying you.”

The Doctor nods, despite the prickle of suspicion, light on the back of her neck, and the trepidation sitting heavy in her stomach. Something about this seems off; everything about this seems off. But then, that’s why they came here, isn’t it? Because she made a promise.

_And I’m going to make good on it._

“Brilliant!” the Doctor gives a grin, and claps her hands together. “Sounds like a mystery. And I _love_ mysteries.”

—————

As it turns out, Anta and Regis haven’t yet arrived by the time Arnold deposits them in a briefing room two hallways down. He takes one look and shakes his head, makes a quick promise to hurry back, then takes off down the hallway muttering something about timeliness. Yaz and the Doctor watch him go, then share a look. Yaz is the first to speak.

“Assistant? Really?”

The Doctor raises her eyebrows. “Oi, what’s wrong with assistant? I’ve known a lot of good assistants in my time. That’s a great cover story, that is.”

Yaz hesitates, then sighs and lets her gaze drop down to the floor. “Maybe. Sorry, I’m just nervous. And excited. But mostly nervous. It’s weird.”

“I can imagine,” the Doctor says softly, and before she can think better of it, reaches out to take her hand. Yaz looks up and a small smile etches its way across her face. 

“We’re almost there though, aren’t we? I mean, we’re going to figure this out. Right?”

“Uh—” the Doctor almost stutters her answer, but fortunately it doesn’t matter, because in that instant, Yaz is not Yaz. She shimmers, then shifts, and for a moment she’s wearing her police uniform, a confused grimace upon her face. Then, just as suddenly, it’s the Doctor’s Yaz again, button-down shirt and jeans, a tentative smile upon her face.

And then Yaz doubles over, her face contorted in pain.

“Yaz—?”

“Oow,” Yaz gasps, and her hand slides free of the Doctor’s grasp to wrap around her chest. “Oh my god, Doctor, I feel like—”

“Yaz!” the Doctor bends down as well, puts a hand on her back. “Yaz, can you tell me what happened to you? From your own perspective?”

“I—” Yaz gasps again, lets out a small cry of pain, and the Doctor goes for her sonic, but then she doesn’t need it. Yaz untenses suddenly, and brings her hands up to rub at her eyes. Then she straightens up, and casts the Doctor a look of confusion.

“I’m…fine,” she says slowly, as if she doesn’t quite believe it herself. She looks down to her hands, then to her chest, her shirt. “Was I…in my uniform?”

“Uh…” the Doctor is staring at her, mouth open. “You were, yes. I think…”

Her sonic is already in her hand, so she goes ahead and gives her a quick scan anyway, and when she brings it close to take a look, her eyes widen. Her mouth forms a hard line, and she gulps. She’s only vaguely aware that Yaz is watching her, until Yaz shifts her weight and pointedly clears her throat.

“Doctor, what is it?” Fear leaks into her tone, and that more than anything gets the Doctor’s head to jerk up, her eyes finding Yaz’s.

“It’s…” Her eyes fall back to the reading, and she sucks in a small breath of disbelief. “Your pressure readings are off the charts. Just like that…thing. Like some enormous weight that doesn’t even exist is pressing down on you, but _how—”_

She doesn’t realize the error of her delivery until she looks up and catches sight of Yaz’s face, pale with fear. 

“But we’re going to figure it out,” she adds hastily, and watches Yaz gulp, then nod, and knows she hasn’t done much to reassure. She opens her mouth to add something more, maybe try again, but before she can, the door creaks behind them. Yaz looks over her shoulder, and the Doctor spins around, plastering a smile upon her face.

“Ah, so you’re our guests.” The women smiles as she enters the room, perfect teeth flashing against dark skin run-through with smile lines. A man troops in behind her, hands combing through his long black hair, and tosses them a tired grin. “You two got names? Arnold didn’t mention, but then, he’s like that.”

“Names,” the Doctor repeats, her mind still half-scattered towards whatever had just happened with Yaz. “Right, names! I’m the Doctor, and this is Yaz, my assistant. We’re here to take a look at whatever that thing out there is.”

“You mean the dot?” the man says. He’s busy looping his hair into what looks like a bun—something the Doctor notes rather jealously—and when he finishes, he brings his hands down to his sides. “That’s great, actually. Maybe with you lot we’ll actually find something.”

“Oi, Regis, _don’t_ call it the dot.” The woman shoots him an annoyed look. “Any moment Arnold is going to turn our comms on, and then we’ll never hear the end of it.”

Regis rolls his eyes. “Not my fault he doesn’t like nicknames. The man has no sense of humor.”

“Neither do you, despite what you think,” Anta grumbles, then flashes Yaz and the Doctor a small smile. “Sorry, we didn’t introduce ourselves. I’m Anta, this is Regis. As you can probably tell, we’ve been going a bit stir-crazy.”

“Yeah, because it’s been _months_ ,” Regis replies. “Months, and nothing. I swear, if today doesn’t pan anything out, I might actually go stir-crazy. Start running naked through the hallways.”

“Please don’t,” Anta says. “That’s a terrible mental image.”

“Cheers on the compliment.” Regis shoots her a grin, which falls as he catches sight of Yaz and the Doctor, wearing twin looks of horror. “Uh, I’m not actually going to do that. Promise.”

“Great to hear.” The Doctor manages a choked nod, then beckons toward the doorway. “So, shall we get started?”

“Actually, it’s that way.” Anta points, and they turn to look behind them, to the back wall, cleared of any blocking equipment or tables. “This is the antechamber before the airlock. Arnold is just setting up the air corridor.”

“Ah, I was wondering why you two weren’t bothering with spacesuits.” The Doctor turns back to look at them. “It’s really that close?”

“Of course,” Regis answers. “And we’ve got the exo-skel gels just in case. Did Arnold give you some?”

Yaz and the Doctor shake their heads, and Regis digs into his pocket, pulls out two small packets, which he tosses, one at a time, to the both of them. “Here. Best to eat it right before we step out. It’s got about three hours of protection, but it only activates if the air corridor fails.”

“Right.” The Doctor closes her hand around the packet, and glances back to see Yaz examining hers with great interest. “How’s the taste?”

Regis flashes a grin. “Lemon-lime.”

“Could be worse.” Anta shrugs. She’s busy at a table next to the wall, checking equipment—spindly probes, artron energy scanners, and what the Doctor recognizes as a crude attempt at a temporal microscope. “Last shipment was Algoti berry.”

The Doctor wrinkles her nose in agreement, just as a crackle of static sounds in her ear. She winces, and out of the corner of her eye, watches Yaz do the same, clapping a hand to her ear. “Ooh, nano-comms? Could’ve warned us.”

“Sorry.” Anta turns around, hands full of equipment, and passes a probe and a scanner to Regis, pocketing the temporal microscope for herself. “Right. You lot need anything, tool-wise?”

The Doctor shakes her head, and holds up her sonic screwdriver. “Got everything I need right here.”

Anta eyes it, then lets out a low whistle. “So _that’s_ where all the funding is going. Gotta say, that looks eons beyond anything we’ve got.”

The Doctor smiles, and pockets it. “You’re not far off.”

“Anything for you?” Regis directs this to Yaz, who looks up in surprise. The Doctor follows his gaze, and turns to find Yaz still white with fear. Guilt settles uncomfortably in her stomach at the sight. “You’re pretty quiet, ain’t you? Assistant gig must not be all that, eh?”

At his words, Yaz dredges up a small smile. “You could say that. You know, with all the bossing around.”

“Oi—” the Doctor begins, but both Anta and Regis are already chuckling, so she just cuts off, mouth turning down into a frown. “I am _not_ bossy.”

“Arnold says the same thing,” Anta chortles, and gestures vaguely in the air. “And yet…”

“I heard that.” An annoyed voice crackles in their ear, and Regis and Anta’s smiles instantly disappear. “I don’t have to tell you when I start listening, you know.”

“You could be polite,” Regis responds, and casts Yaz and the Doctor a grimace. “Anyway, set up that air corridor yet?”

“Yes, and I’m very excited to kick you lot out into it,” comes Arnold’s reply. “Are you all ready?”

“Course we’re ready,” Anta replies, shifting the temporal microscope in her grip. “Old hat, Arnold.”

“Yes, but not for the new people,” Arnold answers, disgruntled. “Best behavior, alright? We don’t want any mistakes. _Especially_ since we’re trying extraction today.”

“Yes, yes,” Regis answers impatiently. “We know. Can we just hurry? Rezik downloaded a new movie, and he said he’d wait til I got back.”

“ _That’s_ what you’re focused on,” comes Arnold’s reply, but then there’s a series of beeps, and the door behind them begins its slow slide open. “Right, airlock’s opened, defenses deactivated. You’re free to step inside.”

They do as he asks, and as soon as they’re safely over the threshold, the door whooshes shut behind them, shrouding the four in dim light. Regis nudges the Doctor, and when she looks over to him, points to her fist, closed over the exo-skel gel. 

“Now’s a good time to eat that.”

She glances to Yaz, and together they comply, popping the capsules into their mouths. It dissolves instantly in a burst of lemon-lime, not entirely unpleasant, and moments later the Doctor feels a thin layer of _something_ creep over her skin. She looks over, and sees Yaz examining her hands, pinching gently at the skin below her wrist.

“Right. You lot ready?” Arnold’s voice comes in another burst of static, and at Anta’s affirmative, the Doctor hears another series of beeps in her ear—buttons being pressed—followed by the now familiar sound of the door sliding open. They watch as it creeps back, slowly, exposing the desolate landscape of the asteroid before them. 

Only a few hundred feet away, directly in front of them, the Doctor recognizes the spot they saw in the hologram. She swallows, and waits until Anta and Regis take a step forward to follow.

“This is it,” she whispers to Yaz as she comes up beside her. “Ready?”

Yaz nods, brow creased in either worry or fear, and whispers, “It’s what we’re here for, yeah?”

The Doctor smiles, and leans in, making sure her voice is kept low. “We’re here for you, Yaz.”

“Right.” The worry doesn’t entirely disappear from her expression, but the ghost of a smile appears on her lips. “Well, don’t say it like that. Makes me sound all important.”

The Doctor shrugs. “You are.” Then, because Anta and Regis are already several feet ahead, she begins to move forward, and waits until Yaz falls in step as well. Then, together, they walk out onto the surface of the asteroid.

It only takes a minute to reach the spot where the mysterious object floats. At least, the Doctor reckons it’s the right place, because it’s hard to tell considering the thing is as good as invisible, at this magnitude. As soon as they arrive, however, Anta brings up the temporal microscope and presses a few buttons, sending up what looks like the circle of an enormous magnifying glass, floating in midair. She plays around with the device a few seconds longer, and Yaz and the Doctor watch as the inside of the circle slowly zooms in, further and further, until at last the floating golden dot makes its appearance.

Once it’s about the size of a baseball, Anta presses a button and stops the machine, satisfied. “There. Now we can actually see what we’re doing.”

“Brilliant.” The Doctor steps forward, pulls out her sonic screwdriver. “May I?”

Anta nods and moves back, watching as the Doctor closes in and points the sonic. She thumbs a button and it whirs, then stops, and she pulls it back, taking a quick glance before moving away, allowing Anta and Regis some space.

“You got what you needed then?” Regis asks, and gestures to the sonic. “On that thing?”

“Should have.” the Doctor is still looking through the readings, frowning. “Need a few minutes to look through it all.”

“Right.” Regis holds up the probe in his hand, and gestures towards the floating orb. “Well then, can we—?”

The Doctor looks up, then glances between the probe and the orb, and purses her lips, indecisive. She doesn’t think the probe will actually do anything, from what little of the readings she’s managed to get through. And the probe, whilst surely advanced for 52nd century technology, is only human technology. She’s guessing. From what she can make out, their new attempt at extracting information is likely to yield nothing. Nada. Zilch.

“Yes, I suppose you can.” She gestures towards the orb. “Knock yourselves out. Or, don’t. Probably best not to, actually.”

Anta grins, and nods for Regis to step forward. He does, probe in hand, as the Doctor half-turns and begins to thumb through the display on her sonic. Yaz turns as well, moving in close beside her. 

“Found anything?” she whispers, with a quick glance over her shoulder. The scientists are busy at work, extending the probe into the space where the orb floats.

“Not yet.” The Doctor frowns, scrunching her nose. “It’s…strange, you know? This is completely unlike anything I’ve ever seen, only—there’s something familiar about it. It looks almost like—like a breakthrough point. As if there’s something outside the universe, putting enormous pressure on several points throughout the galaxy—or farther, I dunno. But what could cause that kind of pressure? It’d have to be massive.”

“Couldn’t it be like, an alternate dimension, or something?” Yaz whispers, craning her neck over the Doctor’s shoulder. “You said there are other universes out there, right? Way to drop that bomb on me, by the way.”

“Sorry,” the Doctor whispers back. “And nah, couldn’t be. Other universes—they _fit._ They don’t sit on top of us, they sit beside. There are some wear-through points, yes, but this isn’t that. This is almost as if somebody has just—taken a giant _something,_ and shoved it into a pocket dimension. Something that shouldn’t fit. But—”

And then she trails off, the blood draining from her face. The screwdriver grows slack in her hand, then slips out of her fingers. Yaz nabs it before it hits the ground, and shoves it back into her hand. When her nerveless fingers don’t grasp it, she slips it into the Doctor’s pocket, and looks up to her, bewildered. 

“Doctor…?” she whispers, then glances quickly back to the other two. They’re deep in their probing, oblivious to what’s happening behind. “Are you…did you figure it out?”

“Stupid,” the Doctor whispers, and slams a palm to her forehead. “Stupid, stupid, that’s what I am! A bloody idiot—”

“Doctor, you’re scaring me,” Yaz says quietly, and the Doctor startles, looking to her in surprise.

“Right,” she mutters. “Right. Yaz, I’m so sorry, but I recognize these readings, and I’m utterly daft for not seeing it before. These—this energy, everything about this—a big thing stuffed into a pocket dimension, oh, I’m so _stupid—”_

“Doctor, what is it?” Yaz demands, her eyes searching the Doctor’s face, insistent. “I don’t care that you’re an idiot, just tell me, _please.”_

“The Time War,” the Doctor whispers, and she knows immediately that Yaz understands, because her eyes grow wide and her mouth opens, forming a silent ‘o’ of understanding. “The Time War, that’s what it is. An enormous event, locked away, and putting pressure on our universe. But that makes sense, that’s _okay—”_

“It doesn’t sound okay to me,” Yaz’s voice drops with apprehension. “That—that sounds dangerous.”

The Doctor shakes her head. “It’s not. It shouldn’t be. They’re pressure points, and if they’re not responding, like Arnold said, then they’re fine, they shouldn’t be reacting. It doesn’t make sense, unless they're using some sort of technology I don't know about—"

Perhaps she _should_ have taken a look at their technology.

Yaz frowns. “I don’t understand. What does this have to do with me, then? Why would—”

And then she cuts off, doubling over in pain, just as a surprised, victorious cry sounds behind them.

“Yaz!” the Doctor drops down, hand on her back, then draws it away just as quickly, because Yaz isn’t Yaz. She’s a police officer again, then she’s wearing ripped jeans and a black t-shirt, then her hair is up in buns, in a braid, chopped short—

“We’ve got it!” Regis crows, and the Doctor tears her eyes off of Yaz, who’s shimmering through so many different timelines it hurts to look at, and whirls around, an awful dread forming in her stomach.

“Stop!” she cries, though she doesn’t know why, but it’s too late. She can see the probe, magnified in the circle, as it enters the glowing orb, watches as the thin needle slides in, and hears, distinctly, three sharp intakes of breath. Two triumphant, one terrified.

And then all hell breaks loose.

The blast knocks Regis and Anta backwards, throwing them completely out of the air corridor, and slams the Doctor flat on her back. Pain sparks in her ear— _there go her comms_ —and impossible gusts of wind rush over her, but she forces herself into a sitting position, groping blindly for Yaz. She didn’t see her when she went down, but then a hand tangles with hers, and she lets out a quick sigh of relief.

“Doctor,” she hears a low whisper by her ear, “Did you see it? Something came through, I—”

“I know, I know.” The Doctor forces herself to her knees, still facing the orb, and keeps one hand bound with Yaz’s as the other goes for her sonic. The orb now can no longer be called that, for it no longer retains the shape of a ball floating in space. Rather, it resembles that of a doorway, hanging suspended only a few inches above the ground, outlined in gold. In the middle, the Doctor can make out the depths of a different space, different stars. In the silence, she can hear screams. 

“It’s the Time War,” she whispers, horrified. “Those bloody idiots, they went digging, they opened it up—”

“Doctor.” Yaz tugs impatiently at her sleeve. “Did you see what they did?”

“I _know,”_ the Doctor growls, harsh and terrified, as she stares down the distant scene of something she’d never wanted to see again. “They’ve no idea what might have come through, Yaz—”

And then she stops, as Yaz’s words register in her brain. There’s something off about her tone, something cool and eager and strangely, terribly familiar, though she’s never heard it before.

“Doctor,” Yaz whispers again, and her fingers give the Doctor’s palm a reassuring squeeze. “Doctor, they let me through.”

The Doctor’s throat goes dry. Her hearts pound a staccato rhythm, quick and scared, and she almost doesn’t want to look. She can feel Yaz’s hand in hers, warm and familiar, and knows that if she turns, it’ll all be completely wrong.

But she has to.

The Doctor swallows, once, then turns and looks into the eyes of the Nightmare Child.

**Notes for the Chapter:**

> okay, if ya'll go digging for what the Nightmare Child is, I'll have you know that I've completely disregarded the description stated on the Doctor Who wiki, which says the Nightmare Child is some kind of advanced dalek. That's lame, lmao. Other descriptions in canon describe the Nightmare child as an incomprehensible being of time born out of the destruction/time paradoxes of the time war. Guess which one I'm going with? not the first.
> 
> Anyway, for all you guys wondering how this fits in, more will be explained in the next chapter! I swear.


	9. Chapter 9

**Notes for the Chapter:**

> Hey guys, I'm sorry this is such a short chapter, but it's necessary because I am evil >:)) Next chapter should be out friday-ish!
> 
> Also, thank you for all your lovely responses to the last chapter. I'm very sorry I haven't been able to give you all individual answers, but unfortunately working on the Fanzine (which will be out in a couple weeks!) has left me with basically no time. But seriously, your comments give me life. And my betas appreciate it too, because I've gone to them multiple times worrying 'does this story have the proper effect? am i doing it right? do you think i should have-'
> 
> Anyway, seriously, thank you all <3

Ages ago, in a war that never happened and doesn’t exist, the Doctor stood and watched the birth of a creature both so glorious and horrifying that she laughed, and laughed, and laughed, because the alternative was to sob. Ages ago, she stood frozen in the midst of a raging battle across time and space, and tossed the final paradox into a maelstrom of unwoven timelines, and knew the consequences would be unforetold, and let it happen anyway.

And the result was the Nightmare Child.

She doesn’t remember the face of the Nightmare Child, because it didn’t have one. It had a presence, and an effect and a petulant, childish temper upon which it struck out entire galaxies, and she watched its birth, and did nothing, then turned and ran, leaving the Nightmare Child to its own devices.

And as children do, it played.

*

The Doctor stares, and resists the urge to run. Yaz is smiling, a slow, creeping smile, and her eyes, whilst not black, are incredibly close. The shimmering, intangible effect is gone. Yaz is here, and solid, and that’s because, the Doctor realizes, she’s not Yaz at all.

She swallows again, feels her throat move dryly, and says, “Hi.”

“Hi.” Her eyes, the Doctor realizes, are the same eyes that have been peeking out of every alternate Yaz she’s seen. A dark, terrifying glint, something entirely other and only now, that she’s staring it in the face, completely recognizable.

Because if the Nightmare Child had eyes, the Doctor thinks, this is what they would look like. 

The Nightmare Child’s grin grows. “It’s nice to see you, Doctor. Did you like my hints?”

“Hints,” the Doctor whispers, and for a wild moment, she has no idea what she’s talking about. Then it hits her; the something familiar, and her own, wildly inaccurate guess, which has led her by coincidence to the right place, the right time.

“I almost didn’t get it,” she says, and wants desperately to sound strong, but her voice is trembling. “It was a bad hint. I only guessed right by accident, you know.”

The Nightmare Child shrugs, unaffected. “It worked, though. And I knew you would get here, in the end. You always do. I’ve been leading you, ever since.”

“But—” the Doctor shakes her head. “That doesn’t make sense. How can you be leading—? You’ve only just got here, I saw you myself. You came through there!”

She flings a hand out towards the orb, which is now no longer an orb. It looks more like a portal, the edges a shimmering gold, the middle gaping open upon an alien view. Inside, glimpses of battle rage across a star-scattered sky. The Nightmare Child follows her gaze, and her smile turns into a smirk. “Since when do I have to be so linear?”

The Doctor stares, mouth gaping, then abruptly turns away, partly to think, and partly because standing so close to that—that thing, wearing Yaz’s face, and Yaz’s voice, and Yaz’s eyes, is one step away from turning her into a puddle on the ground. Her brain is screaming at her to run, and her shaky limbs want to follow the idea.

But she made a _promise._

“It doesn’t make sense,” she whispers again, more to herself, and hears a quiet laugh behind her. “It can’t, that doesn’t—”

Only it can, she realizes with a sinking heart. It can, and it does, because the Nightmare Child is right. There’s no use in moving linearly along a timeline when you have access to the whole of it.

She whirls back around, and jabs a finger at Yaz’s face. “You!” she cries, her face white, finger shaking. So much for courage. “You’re—you’ve infected her, haven’t you? You’re spreading along her timelines in every direction, you’re _poisoning—”_

The Nightmare Child laughs again, the impertinent laugh of a cheeky child. “I’m not infecting her, Doctor. I’m _eating_ her.”

The Doctor sees red flash in her vision. Her hands curl into fists, and she stands there, trembling, not from fear, but from rage. 

“Let her go,” she growls, and steps forward, swallowing the terror in her throat. “Let her go, or I’ll—”

“What?” the Nightmare Child links her hands behind her back and leans away, lower lip sticking out. “Why? I didn’t do anything wrong. I’m just hungry. I’ve been trapped there for so long, Doctor.” She gestures to the portal, glimmering in the air. “You left me there.”

Whatever the Doctor was about to say falls from her lips. She stares, then shakes her head, and runs a shaky hand through her hair. Her fingers flex towards her sonic, but she’s no idea what she can do with it. She has no way to win.

“Why her?” she croaks suddenly. “Why—why Yaz? She wasn’t even closest, you didn’t even need us here. These idiots were always going to open up that point, with or without me. So why?”

The Nightmare Child’s smile grows sickly sweet, and she steps closer. “Why do you think?”

The Doctor shakes her head and takes a step back. Out of the corner of her eye, she notices the portal, glimmering just off to her left. “I’ve no idea. I don’t know what you want with me.”

“Isn’t it obvious?” the Nightmare Child asks, and takes another step closer, prompting the Doctor to take one back. It’s a strained, uncomfortable dance. “I wanted _you,_ Doctor.” She jabs a finger into the Doctor’s chest. “I’ve always been waiting for you, ever since you left me there. What, you didn’t think I saw you? That I wouldn’t know my creator?”

“I’m not your creator,” the Doctor whispers. “It was a _war—”_

“But you finished it,” the Nightmare Child answers. “You were there, and you led that battle, and you threw that final paradox, and I remember when I woke up and looked into your eyes, and watched you _run.”_

Her mouth twists on the last word, pulling down into a sneer. She steps closer again, right up into the Doctor’s space, who leans back and away. “You ran, and left me there. Do you think I wouldn’t find you? I’ve been searching for you ever since, and the minute I saw that chance—”

She grins, and beckons towards the portal, now practically by their side, “I knew you had to be there. So I fixed it.”

“You—you—” the Doctor stammers, trying to think through the banging of her hearts. “You—I led you to Yaz?”

The Nightmare Child’s grin drops into a pout. “Don’t you like me better this way?”

“No.” The Doctor gives a vigorous shake of her head. “No, I don’t like you at all. I’m not—I’m not your creator, or your parent, or whatever you think! I have no responsibility—”

The Nightmare Child frowns. Her shoulders drop. “Then who does?”

“Nobody,” the Doctor whispers. “Nobody does. I didn’t—”

“You _ran,_ ” the Nightmare Child says, lip curling. “You ran, and you wanted to run from her too, didn’t you? Even when I saved your life, twice, you wanted to leave me behind again, and again, and I only wanted to be found. Don’t you understand? You’ve never even known Yaz. You’ve only known me.”

“That’s not _true._ ” The Doctor grits her teeth, her fingers wrapping around her sonic, though she knows it’s useless. “I—I care about Yaz, I love her, and you’re—you’re _evil—”_

“I’m not evil.” The Nightmare Child crosses her arms, frowning. “I am her. How can I not be? I’ve been gnawing away at her timelines all the way back to before you met her, by now. Pretty soon, there won’t be anything left.”

“Let her go,” the Doctor snarls, and with one hand, thumbs a button on her sonic, sending out an emergency set of coordinates to the TARDIS. For Ryan and Graham. She can keep them safe, at least.

She’s not so sure about Yaz. 

The Nightmare Child cocks her head. “I don’t think I want to. I like being in a body. I like being in _this_ body. I like the way you look at me. You know—” she gives a sorry shake of her head. “I’ve only ever wanted to be where you could see me.”

“Great. Seen.” The Doctor glances to the portal, so close she can hear distant sounds of battle. Her hearts are pounding wildly. “Now get out of Yaz, or I’ll—”

“You won’t do anything.” the Nightmare Child grins, confident. “You can’t, not without hurting her. Hurting me.”

The Doctor freezes. Her lips part, as if to say something, then purse into one hard line. Her eyes roam over the Nightmare Child, searching for something she apparently doesn’t find. Then she swallows, hard, and steps closer, erasing the gap between them. With one hand, she reaches out, and pushes a stray lock of hair behind Yaz’s ear. 

“You’re right, aren’t you? If I hurt you, I hurt her.”

The Nightmare Child nods, pleased. “Now you’re getting it.”

“I am.” The Doctor studies her. Her brow is wrinkled, her eyes heavy with something unreadable. She sucks in a breath, nostrils flaring, and lets it out in a shaky sigh. “I’m sorry, Yaz. I do care about you.”

There must be something off about her tone, for the Nightmare Child frowns, her grin falling away. She opens her mouth, but doesn’t have time to respond, before the Doctor wraps her arms around her and pushes them both straight into the portal.

**Notes for the Chapter:**

> Hopefully yall didn't expect that. And hopefully this clears up what the Nightmare Child has been doing to Yaz. Again, if you want to see where I got my inspiration, check out the story I linked in the first chapter, Time v.3.0. Oh, and if anybody has trouble wrapping their head around it, I'll try to explain best I can. I tried to make it pretty clear but you know, words are only words.
> 
> And as the last one goes out to Jolivira, this one goes out to Emily (13stardisfam), who leaves the nicest comments and cheers me on and in general is just a fantastic person, inside and out. Also, her art is amazing, just fyi. Yeah that's right. She doesn't just do gifs.


	10. Chapter 10

**Notes for the Chapter:**

> im so bad at scheduling with this fic fkjdfsjdfsjdfjdf
> 
> I hope you guys like this one, this was one of my fave parts to write. And as always, thank you for all the wonderful replies! I seriously love reading everyone, even if I don't get around to replying. Its like, the whole reason I write.

_Falling—_

_Falling—_

_Falling—_

They’re rushing towards a distant planet below, reddish-beige tones filling her vision. Distantly the Doctor can feel Yaz clinging to her—Yaz, or the Nightmare Child—and realizes that this is one fall that she’s not going to survive. There’s no regeneration energy to save her now, no train to fall through and meet a group of unlikely friends, only blood-splattered death on the surface below.

_I tried,_ she mouths, even as the wind whisks the words away. _I really tried._

And she’s taking Yaz with her, the opposite of what she intended to do. She doesn’t even have time to feel sad, only ashamed, and terrified, and slightly relieved that at least it’s her life going along as well. If it can’t be one for one, it can be both of them, right? An equal trade, if not a fair one.

And then, she feels the timelines shift.

“No!” she cries, though the word is ripped away from her lips immediately. “No, no, no!”

Beside her, right in her ear, she hears Yaz—the Nightmare Child—laughing, laughing, laughing, high and delighted, and around her she can feel the timeline groaning, impossibly, it can’t be happening— 

The wind pushes them off to the side, farther and farther off-course, not that there’s much of an off-course in what must be a 30,000 foot fall. A lake looms into view below them, oblong and purple, and by the time they hit the surface, they’re at such low acceleration that the Doctor only blacks out for a second when they hit.

She loses Yaz in the impact, and wakes up seconds later to blinding pain in her left arm, and sinking fast through purple currents. For a moment she blacks out again, simply from pain, and when she wakes up someone has grasped her hand, and is kicking with her to the surface.

They break through the surface, gasping for air, and the Doctor nearly sinks again, only for Yaz to grab her and jerk her upright, a grin wide upon her face. “Think I’d let you drown that easily?”

The Doctor gasps for air and blinks dazedly, trying to focus. “Yaz?”

The Nightmare Child shakes her head. “’Course not.”

She’s got a great gash on her head she doesn’t seem to notice, and the Doctor sees when she reaches out to take her hand three fingers bent at an odd angle. The Nightmare Child doesn’t seem to pay them any mind. She grabs the Doctor by her shoulder, ignoring her yelp of pain, and begins to kick towards the distant shore.

They flop upon wet, reddish sand, and even as the Doctor collapses upon her stomach, ignoring the sand that coats her cheek, she can hear the Nightmare Child laughing beside her with pure, unadulterated joy.

“That was great,” she gasps, and the Doctor raises her head a millimeter, turns it to see Yaz sitting there, leaning back on hands splayed into the sand. Her head is thrown back in laughter. 

“We shouldn’t have survived,” she says weakly, and lets her head drop into the sand. “I’m…I have to kill you.”

“But Doctor, where’s the fun in that?” the Nightmare Child asks, eyes wide and innocent. “Why don’t we just stay here, the two of us?”

“I…” Sand fills her mouth when she speaks. She wants to raise her head, to spit it out, but doesn’t have the energy. “You’ll try to escape. The portal…”

“Is closed.” The Nightmare Child grins, cocks her head. “What? I’m good. I clean up after my messes. And I’ve plenty to eat here.”

She gestures to the skies above them, and the Doctor looks up, just as a high whistle rings through the air. Moments later, she watches as a missile descends from the heavens and plunges into a mountain miles off. An earth-shattering boom cracks through the planet, and the top of the mountain disappears in a cloud of dust.

The Nightmare Child is watching the mountain disappear with interest. “The Daleks are coming,” she says, and glances to the Doctor, waggles her eyebrows. “Want to meet them?”

The Doctor sighs, and lowers her head once more to the sand. Pressure builds in the back of her throat, and she has the strange urge to cry. Pain throbs through an arm she knows is broken. “Let Yaz go. Please.”

The Nightmare Child shakes her head. “I shan’t. Why would I? I’m having too much fun. And _you’re_ here with me.”

The Doctor fails to suppress a shudder. “Please…why can’t you just leave me alone? I never wanted…I never wanted this. Any of it.”

“Oh, but you made me just the same, didn’t you?” the Nightmare Child grins, baring teeth. “You fought here and died a thousand times, in a thousand different timelines, just like everybody else. You took time and strung it together into loops and paradoxes that you knew wouldn’t work, and did it anyway. You turned the entirety of time and space on its head, and at the end of it, you made me. And now you don’t want it?”

This time, the Doctor makes an attempt to raise herself to her elbows—or to one elbow, upon which she balances precariously, spitting sand. “I never wanted it. And I wasn’t the only one, I wasn’t even the worst. Why not them? Why me?”

The Nightmare Child leans in to her, close enough that her breath tickles her cheek, and the Doctor doesn’t look into her eyes but she can feel the smile behind her teeth, darkly vindictive and quivering with a rage she’s only barely starting to understand.

“Because you made sure to shut the door behind you.”

The Doctor doesn't look at her. She can't. She keeps her eyes glued to the sand, and holds herself still, or as much as she can given she's trembling. She feels stuck, caught under the Nightmare Child’s gaze, and when she finally gets the nerve to look up, and catches Yaz’s face around those eyes, the urge to cry bubbles up even stronger in her throat. There are no waves crashing upon the shore, but failure roars in her ears like a current trapped in a conch shell. Deafening.

The Nightmare Child pulls back, abruptly, and chuckles. “C’mon, Doctor. Don't you want to see the Daleks?”

“I—no, I—” But it's no use. The Nightmare Child leaps to her feet, then pulls the Doctor to hers, ignoring her sob of pain as her arm swings uselessly. Definitely broken. The Nightmare Child feels out her unresponsive fingers, then seems to think better of it and grasps her good hand, for which the Doctor can only be thankful.

“Look,” the Nightmare Child says, and points to the sky. Delight spreads across her face. “They're here.”

The Doctor looks, and her hearts sink. Daleks are swooping down from the heavens, from ships hovering high above, enormous, ugly contraptions floating motionless in the sky.

“Aren't they beautiful?” the Nightmare Child asks, her head tilted back, lips parted, eyes sparkling with wonder.

“No.” Familiar, sickening fear washes over her. Nausea buds in her stomach. “Is this it then? You want to kill me?”

“What?” The Nightmare Child’s head snaps around to look at her. “Kill you?”

She shakes her head softly. “Now Doctor, why would I want to do that?”

The Doctor stares at the Daleks descending, already firing into distant battlements. She can see far off troops running out to meet them, ships rising laboriously to fight. They'll all lose, she knows. And soon enough, the Doctor and the Nightmare Child will be caught in the crossfire.

“What do you want, then?” she asks, her voice cracking, maybe from fear, maybe from the sand she's swallowed. The Nightmare Child laughs again, and grips her hand, squeezing her knuckles hard enough to hurt.

“Doctor,” she says, and gives her an impish smile. “I want to _run.”_

And then she takes off, dragging the Doctor behind her. The Doctor stumbles, nearly falls, and tries to jerk away, but her grip is immovable—an iron vice. And then she realizes that it's beside the point, letting go, because she can't; to let go is to leave Yaz, or whatever is left of Yaz, and now that she can't kill her, she sure as hell can’t leave her.

The Nightmare Child laughs, and pulls her, staggering, straight towards the fight, which is drawing closer and closer with every step. Daleks criss-cross the sky, screeching, and booms fill the air, as missiles streak overhead so low the Doctor can't help but duck. Her ears are ringing, her hearts pounding, and with every step she nearly sinks to the ground from dead exhaustion. And the Nightmare Child keeps running.

“Let me go,” she gasps, as a Dalek sweeps so low she has to push them into a timeline where it doesn't see them. “Let me—”

“Nope!” The Nightmare Child calls, then pulls up short, yanking the Doctor forward. The Doctor nearly tumbles to the ground, but rights herself just in time, hissing as pain jabs through her broken arm. 

“We’re here!” The Nightmare Child exclaims, and drops the Doctor’s arm to raise her own to the sky, spinning in joyful circles. They’re right in the middle of it now, or nearly so. Overhead, Dalek lasers plow into an enormous battleship, which groans, and begins to drop. Hundreds of meters away, flames bloom over hovertanks, and troops run screaming, dropping like flies as Daleks run them down one by one.

“It's just a little one, isn't it?” The Nightmare Child frowns, her chin dropping into her hand. “Just a skirmish.”

“It’s a rout,” the Doctor says, and closes her eyes. She's seen a million like these, tiny battles on the outskirts of a war the participants can't even comprehend, the dregs and the human-shaped lot of the universe simply blotted out, by the Time Lords as often as the Daleks. Too small to matter in a war that spans the universe.

“Well, it's fun enough, yeah?” The Nightmare Child turns to her, eyes sparkling with mischief. “And what if I—”

She waves her hand, and the timelines creak and shift again, rusty as nails on chalkboard. The Doctor realizes what she's about to do moments before she does it. She whirls to face the battlefield, the color draining from her face, and catches it just in time.

“No,” she gasps. “You can’t—”

But it’s too late, because now, in this timeline, the native troops have had time to set up their final defense before the Daleks arrived—a string of atmosphere bombs strung across the sky, a final desperate solution. In this timeline, the Doctor knows that someone, somewhere, is pushing that button.

She watches as mushroom clouds bloom across the sky.

Fire begins to rain down. Dalek ships veer, and collide. In moments, the stars are gone, blocked out with red and black and gray. The entire atmosphere turned to so much dust. In minutes, the Doctor realizes, they’ll never see the sun again.

She spins back around, jabs a finger at the Nightmare Child. “You _murderer—”_

“Huh?” The Nightmare Child wrinkles her nose, an eerie echo of Yaz’s confusion. “Doctor, don’t you remember? This is the same tactic you used against the Daleks during the battle of Karsine. You won.”

The Doctor’s finger sags. She stares, dumbfounded. “I—what?”

The Nightmare Child frowns, her brow crinkling. Playing at perturbed. “You don’t remember, do you? A small fight, inconsequential in the grand scheme of things. Not that it matters.” She smiles, teeth flashing. “After you locked us all away, we’ve been replaying every battle ever since. And nobody can decide on a winner.” 

The Doctor can feel her two hearts beating, a sure sign that she’s alive, but she can’t breathe. She feels like somebody’s taken a hammer to her chest. “I didn’t mean to forget.”

The Nightmare Child cocks her head. “You forgot about me.”

The Doctor rears back, and shakes her head vigorously. Her words come out in a hiss, low and feral. “I never forgot about you. Unfortunately for me.”

The Nightmare Child’s smile drops. She steps forward, oblivious to the rain of fire around them. A thin layer of ash is coating over everything, dusting the Doctor’s shoulders and her hair, irritating her nose. She can see the same layer settling over Yaz, watches a flake settle on her nose, and has the strangest urge to brush it away. She stifles it.

The Nightmare Child moves closer, stepping right up to her chest, those almost-black eyes shining with hate, and something else the Doctor can’t name. The Doctor stands stock-still, barely breathing, as the Nightmare Child reaches up to touch her face. Ash comes away on the pads of her fingers, and she examines it for a moment, before brushing it off on her jeans. 

“I waited for you,” she says after several moments. She doesn’t look up, still examining the pads of her fingers. “From the moment I came into being, and I saw you, I knew.”

She looks up, and smiles, tucking her fingers into the pocket of her jeans. “I am a being of pure time. I am here now, and in every other moment. I exist where I choose to.” She shakes her head. “And I choose to be here. Don’t you see?”

The Doctor shakes her head, and tries to swallow, but her throat is too dry to do so. “No. I don’t see. Why are you here? What makes me so—”

She trails off into silence, just then, because she gets it. The Nightmare Child tilts her head, watching the realization hit, and a smirk plays at her lips. The Doctor shakes her head again, slowly, horrified, as if to deny. “No, that doesn’t make any sense, you’re a _monster,_ you can’t—”

She’s always been so bad at recognizing love. 

The Nightmare Child’s smirk shifts into a surprisingly soft smile, so close to Yaz’s it hurts, and gives her a playful poke in the chest. “Now you’re getting it.”

The Doctor stands frozen, too bowled over to respond. She stares into Yaz’s face, into those eyes that are full of hate and something she can only now name, and feels an ugly new feeling settle over her. It’s disgust, but that’s familiar to her, and it’s fear, but that’s familiar to her as well. Nestled between the two of them now is something she wants to pinch herself to wake up from, because she’s not sure she can reconcile the feeling with the monster standing in front of her.

It’s compassion. Compassion, and a hint of guilt.

“I left you,” she sounds it out slowly, half-afraid to hear it aloud. “I left you there, when I ran. And ever since—”

“You made me.” The Nightmare Child reaches out, slips her hand into the Doctor’s good one. “And then you abandoned me. What was I supposed to do, but survive?”

“You killed,” the Doctor whispers. “Everything in your path, you ate them all up, I remember—”

The Nightmare Child shrugs, her lip curling petulantly. “What was I meant to do? I was born out of war and violence and time gone wrong, and nobody was there to show me otherwise. The only thing I saw was you, Doctor. And you didn’t want me.”

Without warning, a voice sounds in the Doctor’s mind, a voice from what seems like eons ago though it couldn’t be more than a few weeks. Defensive stance, eyes hurt deep-down.

_You can barely stand to look at me._

“I’m sorry.” It’s more of a sigh than a statement, barely above a whisper, and she’s not sure who she’s talking to. “I’m sorry. I wasn’t…everything I could be. I haven’t always been. I’ve tried, but…sometimes I fail.”

She lets her eyes flutter shut, feels Yaz’s hand warm in hers, listens to the cracks and booms of a dying planet around them. She can feel the timelines twisting in such a way that the two of them stay alive, unharmed. She’s not sure who’s doing it. Her hearts pound dully in her chest, a double _thump-thump,_ and she thinks how she’s alive, and then she thinks about how she’s failed. The taste of it is thick on her tongue. 

She thinks of Yaz, on those instances where she managed to look past the impossibility swirling around her and saw the girl beneath, and wishes she had seen it more often. She thinks of a thousand nameless battles fought and won and lost in the Time War, and a thousand monstrosities she’s most likely responsible for, and thinks lastly of the Nightmare Child, standing right in front of her, hate and love in her eyes. She wonders if she could have done better, all those times. She figures she probably could have.

But then, she thinks, the past is the past in every other sense of the word.

And she made a promise.

The Doctor opens her eyes. They’re still holding hands, the two of them, and the Nightmare Child is watching her with a smile that’s not entirely unpleasant, with an eager sort of hope in her eyes. The Doctor looks to their hands, then looks to her, and knows this is going to hurt.

She shakes her head. “I’m sorry I wasn’t there for you. But I made a promise to someone else.”

And then she jerks her fingers out of the Nightmare Child’s grasp, and drives her shoulder into her chest, gritting her teeth as pain explodes up her arm. The Nightmare Child staggers back, surprise and betrayal on her face, but before she can do anything the Doctor is already reaching for timelines, shuffling through them, searching, searching—

She grasps and pulls, throwing caution to the wind because hell, she’s in the bloody Time War, and with enormous effort, yanks the entire planet around.

The mushroom clouds are gone, because they never exploded. The Daleks still rage, and the troops still run. But they’re not done yet. Not entirely.

The Doctor blinks, and nearly sags, then folds like a plastic chair, falling to her knees. The sand is hard on impact, but she’s too exhausted to care. The stars are shining again. There’s even a couple moons she hadn’t bothered to notice before, thrown up in the sky.

Then a weak shadow falls over her, and she looks up dizzily into the face of the Nightmare Child. It’s all rage now, balled fists and white hot fury running through a heaving chest and set jaw.

“You’ve ruined my fun,” she snarls, and kicks childishly at the sand, throwing up pebbles in the Doctor’s face. The Doctor ignores it, and simply raises her chin to look her directly in the eyes.

“Let her go,” she rasps. “Let Yaz go. And let us leave.”

The Nightmare Child purses her lips, petulant. “No,” she says, and turns her back on the Doctor. “You’re mean, and I don’t like you anymore.”

“Then kill me.” The Doctor sways in place, unsteady. “Wouldn’t that be a treat, all the life I’ve lived? Kill me, and eat me up, all my timelines, I don’t care, but leave Yaz _alone.”_

“No!” The Nightmare Child whirls back around, and stomps toward her. “I won’t! Why should I? I like Yaz, I like being this physical form, and you—you like me like this, I—”

“I like Yaz,” the Doctor answers, her voice steady. “And I miss her. And I made a promise, one I’m not giving up on.”

At this the Nightmare Child laughs, harshly, nearly doubled over. “Oh, you like Yaz? Yaz, who you don’t even know? Yaz, who was always me, since you met her? You don’t even know which version of her you like! You want to try and tell me—”

She spreads her arms wide, and the Doctor blinks, because suddenly she’s not the only Yaz standing there. There are Yaz’s trailing off to each side, and behind, like a three-way mirror, there and somehow not, and each one is different. She spots footy Yaz far down to the left, and at least a dozen in police uniforms, another twenty paramedics, a Yaz in a suit, plaid shirt, short hair—

The Nightmare Child laughs again, but the sound is strained. “Doctor, I _am_ Yaz. I’ve been eating her timeline since I first fell into her, and it’s been the best meal I’ve had in _eons._ You can’t save her now, because there’s nothing left. It doesn’t matter what you want.” Her mouth twists on the word _you_ , and she spits out the word _want_ like it’s dirty. “I am all there is. You can only have me, or nothing at all.”

The Doctor stares, utterly disoriented, because every Yaz is flickering, blinking in and out of existence and blimey she’d forgotten how much that hurts to see, and she’s trying to find focus, trying to make sense of something, but the only Yaz staying steady-solid is—

Her.

Her Yaz, right in the middle, wearing that same button-down shirt and jeans, and the smug, vindictive smile of the Nightmare Child. The Doctor makes eye contact, and watches her smile widen, turn insolent, as if challenging her. Like a child. 

_Make me._

The Doctor nearly falls over twice as she staggers to her feet. The sand slips beneath her shoes, and she stumbles, then lurches forward, to the multitude of Yazs, to the Nightmare Child, standing in the middle of it. 

She draws up short less than a foot away, and sways, unbalanced. The Nightmare Child looks her up and down, then crosses her arms, unimpressed.

“What’s your game, Doc?” she says.

“Give her back to me,” the Doctor states hoarsely, and when the Nightmare Child shakes her head, heaves out a shaky breath.

“She’s not here. She’s gone,” the Nightmare Child says, her tone just a tad too forceful.

The Doctor shakes her head. “I know she’s there. And I’m going to find her.”

“Oh?” the Nightmare Child raises an eyebrow. “How?”

“Like this.” The Doctor reaches out, cups Yaz’s face in her hands. The Nightmare Child’s eyes go wide in surprise, but before she can react, or draw away, the Doctor presses her forehead against hers. 

The mirrored Yazs disappear in a single flicker. Together, the Doctor and the Nightmare Child crumple.

They’re out before they even hit the ground.

**Notes for the Chapter:**

> Okay, so I looked it up, and you can survive a fall from that high up. Is it likely? No. but where you land and wind resistance etc etc makes a difference, and of course, with the Nightmare Child manipulating things...
> 
> Also, I hope my quote at the start of the story makes some sense now. And credits to the wonderful Hellynz for pulling it for me, she probably gets this story better than I do.


	11. Chapter 11

**Notes for the Chapter:**

> last chapter guys! i hope this one fulfills all your expectations (or at least, gives you all a satisfying ending). seriously, thank you guys so much for sticking with this. i've truly enjoyed seeing all your reactions, your comments and everything. it's a wonderful feeling as a writer. i mean, other than writing for myself, it's all for you guys, so.

The Doctor lands on a grassy surface, hard underneath, and staggers before finding her balance. Then she straightens, and looks around.

She’s standing on an asteroid, she realizes, but it’s not the asteroid they came from, the barren rock with the shabby lab perched atop it. Rather, it’s an asteroid coated in grass and flowers, barely larger than a swimming pool, and with what has to be an oxygen bubble placed around it. Flowers and bushes bloom around the edges, setting the air alight with fragrance.

It’s the hanging gardens of Rhourus, she realizes. Set into an asteroid belt between the twin Rhourus planets. With the greatest view of the galaxy in the entire system.

She’s been here before.

_They’ve_ been here before.

“Hi, Doctor.”

She turns, and spots her immediately. There’s a bench just a few feet off the edge, set in the direction of the several swirling nebulas. Upon it Yaz swings her trainers, wearing the same button-down shirt and jeans she wore the last time the Doctor saw her.

Only she’s completely solid.

The Doctor takes a step closer, and then another. Tentative. “Hi, Yaz.”

Yaz doesn’t immediately answer. She’s staring out at the stars, and as the Doctor watches, she heaves a sigh.

The Doctor takes another step closer.

She notes with some relief that her arm is working here. She’d expected as much, for her dream-self to be whole, but it’s good to feel it anyway. When she flexes her fingers and swings her arm experimentally, she finds it free of shooting pains. 

She moves closer, one foot at a time. A final step bridges the gap, and then she’s standing next to the bench, looking down at a Yaz she desperately hopes is her own.

“Yaz,” she says, in a low, rough voice. “It’s you, yeah?”

Yaz looks up at her then, just for a moment, before looking away, her gaze dropping back to the stars. Her eyes are warm, the Doctor notes, and dark, and void of the dangerous glint of the Nightmare Child.

“Yeah,” Yaz says, closer to a sigh. “It’s me.”

For a moment, the Doctor just stands there, tight, painful happiness clogging her throat. Then, because she can’t trust herself to speak, she plops down on the bench, right next to Yaz, and rocks slightly, before her fingers curl underneath the seat.

They sit for several seconds in silence. Then the Doctor clears her throat, and gestures toward the glittering expanse. “So this is your mind?”

Yaz shrugs. “I dunno. I guess so. This is where I’ve been, ever since.”

“Right.” The Doctor nods, one quick bob. “Ever since what, exactly?”

Again, Yaz simply shrugs. “Not sure. It’s a funny way of telling time, isn’t it?” she frowns, thinking. “I don’t think it’s been _too_ long—I think it started when they opened that thing, didn’t it?”

“I think so, too,” the Doctor says, and Yaz glances to her, just for a moment, her expression unreadable. “That was when the—the—”

“Yeah,” Yaz finishes for her quietly. “I know. Only now I realize, I’ve been feeling it even longer than that. And I don’t know how to make sense of it. Like it’s been eating me from the inside out, starting with the bit at the lab, and just moving further and further back. Is that how it works?”

She must realize the Doctor is watching her as she speaks, for when she looks over, she catches the Doctor’s gaze immediately, her expression sober.

“It is.” The Doctor swallows dryly, licking her lips. “Uh, it is. It has you, Yaz, and I don’t know how to make it go away. The only thing I could think of was to come in and get you—”

Yaz smiles. “That was pretty smart, actually. I saw that.”

The Doctor stops, confused. “Saw that?”

“Oh, yeah.” Yaz is staring at her shoes, which have stopped kicking. “I saw all that, when you pushed us in, and when we were falling, and that war down there. Like, I wasn’t there, but I saw it, you know? It was downright terrifying, if I’m being honest.”

“Oh.” The Doctor doesn’t know what else to say. “You saw—”

“You tried to kill me.” She says it short and bitter, and the Doctor nearly bites her tongue off hurrying to shut up. “I saw.”

“I’m sorry, Yaz. I was—I was scared.”

“Is that why you ran?”

This question pulls the Doctor up short. “Ran?”

“With the Nightmare Child.” The kicking has started again. Back and forth, back and forth, like a child seated at a too-high table. “That you made it, then you ran away? Because you were scared?”

“I—” Lies and bluster spring to her mind, the half remembered instincts of a Doctor much more confident than she’s feeling right now. She goes with the truth. “I think so, yeah. I do that a lot, running when I’m scared. Sometimes I dress it up in other things, but it’s usually because I’m scared.”

“Oh.” If this assuages Yaz, she doesn’t show it. “Well, I guess it’s good you admit it.”

“Maybe.” Again, they lapse into silence. The Doctor studies Yaz, who stares once more at the stars, the reflected light setting her eyes a-glitter. In the dark, she looks ethereal, but entirely human. 

“You know, this was my favorite place we went.”

Her comment startles the Doctor out of her reverie. “Really?”

Yaz nods. “Yeah. These gardens. I thought they were so magical. I always wanted to come back.”

“I didn’t know.”

Yaz shrugs. “I never told you. Maybe I should have.”

“Maybe I should have listened better.” 

Yaz doesn’t say anything, but continues to watch the stars, as the Doctor watches her. Something is sitting heavily at the back of her mind, something pressing underneath the panic of time quickly slipping by. She knows she can’t stay forever. Sooner or later, she’ll have to go back. And she still doesn’t know how to take Yaz with her. Only now, sitting side by side in this peaceful, silent garden, she's beginning to realize that she's not sure she can.

“Yaz?” she asks suddenly, and there’s something desperate in her tone, maybe, that has Yaz looking over sharply. “I should apologize, probably. I don’t think I treated you properly. More like an experiment and not a human being, and it took me too long to realize you were my friend under all that temporal nonsense. I should have done a lot more right by you, and I know I made a promise, but—but I have to go back, pretty soon, and I don’t know how to take you with me.”

She rushes it, feels sand slipping through her fingers, time falling away, and knows that she can’t stay long. Her saving throw, and all she’s done is talk. And it’s not even good, clever talking.

Though it might be what Yaz needs to hear.

Yaz’s eyes roam over her face for several long moments, before she smiles. And it’s an open smile, not a trace of bitterness or ill-spirit. It’s just sad.

“Thanks, Doctor. And I don’t think I wanted much. I just wanted you to see me, you know? But I think you do, now.”

“Oh.” The Doctor feels this as a dull thud, directly to her chest. Failure, once more, washes over her, and she wants to cry. “I do see you, Yaz. I saw you long ago. I think you’re brilliant, absolutely ace.”

“Really?” Yaz asks, and smiles, a big, hopeful smile that makes the Doctor’s hearts crack in half. 

“Course I do,” she replies, and tries unsuccessfully to blink back tears. “I don’t—god, I’ve bungled this completely, haven’t I? From the moment we met, I—”

She gestures uselessly between them. “I messed it up, and I keep messing up, and I’m too late to save you. I can’t even save the bloody Nightmare Child, not that I even knew I could’ve in the first place.”

“You could’ve?” Yaz blinks in surprise, and the Doctor’s hearts sink, because now it’s not Yaz, anymore. Her eyes glitter dimly, and they’re not her own. The Doctor purses her lips into a thin line.

“Have you been here the whole time?” she asks, and prays the answer isn’t what she thinks. “Just now, when we were talking. Was it—was it you, and not Yaz?”

The Nightmare Child looks taken aback for a moment. Then, surprisingly, she drops her gaze to the bench, and shakes her head, like a kid caught lying.

“No. I was just listening in.”

“Oh.” The Doctor has no idea what to do with this information. “I have to leave soon, you know. I have to wake up.”

This doesn’t invoke the reaction she expects. The Nightmare Child looks up at her, and tilts her head, frowning. Contemplating.

“Did you mean that, what you said?”

“What did I say?”

“That you could have saved me. That you would have.” The Nightmare Child is eying her carefully, expression unreadable. The Doctor stares, mouth slightly ajar, then snaps it shut and gives a slight nod.

“I would, if I’d’ve known that I could have.”

“You didn’t, though. You should have known.”

“I should have.” The Doctor tilts her head in acknowledgment, eyes still on the Nightmare Child. “I made a lot of mistakes. I have a lot of excuses, too. But sometimes it doesn’t matter, does it? The reasons you did things. It’s the hurt that matters.”

The Nightmare Child’s jaw tightens. “It does.”

“Then I’m sorry.” 

“Okay.” 

She turns to the stars and studies them for a moment, then lets out a sigh, barely a whisper of sound. Then Yaz is back, so quickly the Doctor barely realizes the switch. She’s looking at the Doctor, in exactly the same way the Nightmare Child had stared at her moments before.

“You have to go, don’t you?”

The Doctor winces, because even as she sits, still as she can, she can feel consciousness dragging at her, digging its claws into her back. “I do. Yaz, please—can’t you come with me?”

It’s stupid, and desperate, because she’s seen enough to know that the Nightmare Child is completely entrenched in Yaz’s subconscious, There’s no dragging her back without the Nightmare Child leaving, and she’s no idea how to do that. But she tries anyway.

“Yaz—” she takes her hand, pulls it close to her chest, clasping it in both fists. “Please, come with me, I—”

But Yaz is shaking her head, a sad smile upon her face. “I can’t. You know I can’t. It’s not up to me.”

“Then who is it—” the Doctor asks, but she doesn’t get to finish, for in that moment the entire world dissolves around her, and she plunges into blackness.

“No!” she cries, reaching out uselessly towards nothing. “No, no, no!”

But even her own cries fade into nothing, followed quickly by the Doctor herself.

————

She’s falling.

She’s falling, plummeting towards the earth, regeneration energy coursing in her veins, hotter than the atmosphere she’s burning through, and she wants to scream, but the wind has long since pushed the air from her lungs—

She crashes straight through the roof of a train, and stands up to see five people standing there. Not three, five. She stares confusedly at the three originals, then spins around to face the other two, cowering underneath that giant floating ball of tentacles. Quickly, she grabs a sparking cable and shoves it straight into the writhing mass, forcing it back. 

“That should buy us some time,” she says, brushing the dirt off her suit, then looks to the two standing there, the man, or boy, and the police wo—

_Oh._

The Doctor staggers, nearly falling to her knees under the weight of so many memories. Of a girl who shouldn’t exist and a monster that ate her, and an apology that maybe, must have, sent the universe spinning in the right direction, because Yasmin Khan is here, and confused, and very much _real._

“Yaz,” she gasps, and watches her take a step back in apprehension, flashlight shining directly into her face.

“How do you know my name?” she asks, blustering as if she’s trying to be authoritative, but doesn’t know how.

“Yasmin Khan,” the Doctor pronounces it proudly. “Yaz to your friends.”

“Yeah…?” Yaz stares at her, fear and uncertainty flip-flopping. She looks up to the hole in the roof, then to the Doctor. “Um, excuse me madam, but I don't know you. Why’re you calling me Yaz?”

The Doctor just grins, and sticks her hand out, waiting for an embarrassingly long second until Yaz tentatively takes it. Then she pumps it up and down, grinning like an absolute loon, but too happy to care. “To your friends, yeah?”

Yaz nods once, nonplussed. The Doctor’s grin widens.

“Well, guess what? I’m calling you Yaz, cos we’re friends now.”

**Notes for the Chapter:**

> not shown: in this new timeline, the doctor dragging the fam to that asteroid and ripping into arnold and his team for their stupidity.
> 
> i keep debating between explaining just how the ending makes sense or not, because i feel like it might be a bit confusing on surface view, but i swear it makes sense. i mean, let me know if you don't think it does, by all means. but i promise, my poor brain cell (the last one, bless him), worked overtime figuring this out.

**Author's Note:**

> Sorry about the shortness, but the next one will definitely be longer! And as always, I would love to hear what you think :)


End file.
